Read the following passage and mark the letter A, B, C, or D on your answer sheet to indicate the correct word or phrase that best fits each of the numbered blanks from 31 to 35.
In recent years there have (31)_________many articles on air polution in newspapers and magazines. Scientists all over the world have warned that our atmosphere is becoming more and more contaminated, and that Man, through his carelessness, may run (32)_________of pure air to breathe.
Automobiles and industries mainly account (33)_________air pollution in most cities. They pour into the air such gases as carbon monoxide, sulphur and nitrogen oxides, which are very harmful (34)_________humans. Worrse still, these gases, a series of chemical changes, turn into toxic acids. They fall down in "acid rains", raising the acidity in the air, soil and water to dangerous levels and affecting not only tress but also fish and other wildlife. Many industrial countries in Europe and North America have suffered bad effects (35) ________  those "rains”.
(31).................

Stars have been significant features in the design of many United States coins and their number has varied from one to forty-eight stars. Most of the coins issued from about 1799 to the early years of the twentieth century bore thirteen stars representing the thirteen original colonies. Curiously enough, the first American silver coins, issued in 1794, had fifteen stars because by that time Vermont and Kentucky has joined the Union. At that time it was apparently the intention of mint officials to add a star for each new state. Following the admission of Tennessee in 1796, for example, some varieties of half dimes, dimes, and half-dollars were produced with sixteen starts. As more states were admitted to the Union, however, it quickly became apparent that this scheme would not prove practical and the coins from A798 on were issued with only thirteen stars-one for each ofthe original colonies. Due to an error at the mint, one variety of the A828 half cent was issued with only twelve stars. There is also a variety of the large cent with only A2 stars, but this is the result of a die breakand is not a true error.

The word “bore” in line 2 is closest in meaning to ________ .

Choose the word or phrase among A, B, C or D that best fits the blank space in the following passage:

"Women’s Rights, rights that establish the same social, economic, and political (1)…. for women as for men. Women’s rights guarantee that women will not face (2)… on the basis of their sex. Until the second half of the 20th century, women in most societies were denied some of the legal and political rights accorded (3)… men. Although women in much of the world have gained significant legal rights, many people believe that women still do not have (4)….. political, economic, and social equality with men.
 Throughout much of the history of Western civilization, (5) ….. cultural beliefs allowed women only limited roles in society. Many people believed that women’s natural roles were as mothers and wives. These people (6)….. women to be better suited (7)……  childbearing and homemaking rather than for involvement (8)….. the public life of business or politics. Widespread belief that women were intellectually inferior to men led most societies to (9)….. women’s education to learning domestic (10)…. . Well-educated, upper-class men controlled most positions of employment and power in society."

3. Until the second half of the 20th century, women in most societies were denied some of the legal and political rights accorded (3)… men.

Read the following passage and mark the letter A, B, C or D to indicate the correct answer for each of the blanks from 6 to 15

 
Revising for exams is not as easy as it looks. You will need to work out which routine suits you best, and then stick to it. Some people like studying at night when it’s quiet, whereas others find the early morning is a good time to get things done. You might enjoy (6)…….. to music while you revise, but this can be (7)……... Can you really concentrate (8)……….. two things at once? So think (9)……… you turn your radio on. Your (10)…….. is also important while you are revising. This may be a more than usually (11)………. period of your life, when you should take extra care to eat properly. No missed meals, or junk food, or (12)…….cups of coffee! Get plenty of exercise as well. If you have got fed up with (13)……. you’re doing, or find it hard to concentrate, go for a walk to clear your head. (14)……. exercise will help to keep your body fit and your brain working (15)………… Finally, you also need to take time off. Go out occasionally, see your friends, and make time to relax. Then you will return to your studies fresh and full of enthusiasm.

9................

Read the passage carefully and choose the correct answer

It has been thought that women are the second class in citizen, and men are the first. There is not a real equality of opportunity for men and women. Years ago, people were living in a man-dominated society. Women had to obey their husbands and fathers absolutely. Women's place was in the kitchen and women's work was housework. In many places, women were not even' allowed to go to school. Women had no rights, even the right to choose husband for themselves. Men usually occupied high positions in society so they thought they were more intelligent than women. Men often considered women as their property. Sometimes, they were mistreated by their husbands and suffered the problem as a fate. Many parents did not even want to daughters.

Despite the progress, there remain outdated beliefs about women's roles, traditionally passed down from generation to generation. Men are commonly seen as the strong bodies, bread-winners in the family and key leaders in society, while women are restricted to being housewives and child bearing and care, and housework such as washing and cooking.

According to social surveys, many women in the 21^st century still have to work over 12 hours a day including working in offices and doing countless household chores without any help from their husbands. In some regions, the labor of women is not recognized despite the hardships they endure to support the whole family. Moreover, women are the direct victims of family violence, especially in rural areas.

Thanks to the women's liberation movement, nowadays women have proved that they are equal to men in every aspect. An average woman has weaker muscles than an average man but she may be as intelligent as he is. Women can do everything that men can, and women can do one thing that no man can: they produce children.

Years ago, women are not allowed ________.

Read the following passage and mark the letter A, B, C or D to indicate the correct answer for each of the blanks from 6 to 15

 
Revising for exams is not as easy as it looks. You will need to work out which routine suits you best, and then stick to it. Some people like studying at night when it’s quiet, whereas others find the early morning is a good time to get things done. You might enjoy (6)…….. to music while you revise, but this can be (7)……... Can you really concentrate (8)……….. two things at once? So think (9)……… you turn your radio on. Your (10)…….. is also important while you are revising. This may be a more than usually (11)………. period of your life, when you should take extra care to eat properly. No missed meals, or junk food, or (12)…….cups of coffee! Get plenty of exercise as well. If you have got fed up with (13)……. you’re doing, or find it hard to concentrate, go for a walk to clear your head. (14)……. exercise will help to keep your body fit and your brain working (15)………… Finally, you also need to take time off. Go out occasionally, see your friends, and make time to relax. Then you will return to your studies fresh and full of enthusiasm.

8.......................

Why is it that flying to New York from London will leave you feeling less tired than flying to London from New York? The answer may be a clear case of biology not being able to keep up with technology.
Deep inside the brain there is a "clock" that governs every aspect of the body's functioning: sleep and wake cycles, levels of alertness, performance, mood, hormone levels, digestion, body temperature and so on. It regulates all of these functions on a 24-hour basis and is called the circadian clock (from the Latin, circa "about" + dies "day"). This body clock programmes us to be sleepy twice a day, between 3-5 a.m and again between 3-5 p.m.
Afternoon tea and siesta times are all cultural responses to our natural biological sleepiness in the afternoon.
One of the major causes of the travelers' malady known as jet lag is the non-alignment of a person's internal body clock with clocks in the external world. Crossing different time zones confuses the circadian clock, which then has to adjust to the new time and patterns of light and activity. To make matters more complex, not all internal body functions adjust at the same rate. So your sleep/wake may adjust to a new time zone at one rate, while your temperature adjusts at a different pace. Your digestion may be on a different schedule altogether.
Though we live in a 24-hour day, the natural tendency of the body clock is to extend our day beyond 24 hours. It is contrary to our biological programming to shrink our day. That is why traveling in a westward direction is more body-clock friendly than flying east. NASA studies of long haul pilots showed that westward travel was associated with significantly better sleep quantity and quality than eastward flights.
When flying west, you are "extending" your day, thus traveling in the natural direction of your internal clock. Flying eastward will involve "shrinking" or reducing your day and is in direct opposition to your internal clock's natural tendency. One of the more common complaints of travelers is that their sleep becomes disrupted. There are many reasons for this: Changing time zones and schedules, changing light and activity levels, trying to sleep when your body clock is programmed to be awake, disruption of the internal circadian clock and working longer hours.
Sleep loss, jet lag and fatigue can seriously affect our ability to function well. Judgment and decision-making can be reduced by 50%, attention by 75 percent, memory by 20 percent and communication by 30 percent.
It is often suggested that you adjust your watch as soon as you board a plane, supposedly to try to help you adjust to your destination's schedule as soon as you arrive. But it can take the body clock several days to several weeks to fully adjust to a new time zone.

The word "it" refers to .....................

Many ants forage across the countryside in large numbers and undertake mass migrations; these activities proceed because one ant lays a trail on the ground for the others to follow. As a worker ant returns home after finding a source of food, it marks the route by intermittently touching its stinger to the ground and depositing a tiny amount of trail pheromone – a mixture of chemicals that delivers diverse messages as the context changes. These trails incorporate no directional information and may be followed by other ants in either direction. 
Unlike some other messages, such as the one arising from a dead ant, a food trail has to be kept secret from members of other species. It is not surprising then that ant species use a wide variety of compounds as trail pheromones. Ants can be extremely sensitive to these signals. Investigators working with the trail pheromone of the leafcutter ant Atta texana calculated that one milligram of this substance would suffice to lead a column of ants three times around Earth. 
The vapor of the evaporating pheromone over the trail guides an ant along the way, and the ant detects this signal with receptors in its antennae. A trail pheromone will evaporate to furnish the highest concentration of vapor right over the trail, in what is called a vapor space. In following the trail, the ant moves to the right and left, oscillating from side to side across the line of the trail itself, bringing first one and then the other antenna into the vapor space. As the ant moves to the right, its left antenna arrives in the vapor space. The signal it receives causes it to swing to the left, and the ant then pursues this new course until its right antenna reaches the vapor space. It then swings back to the right, and so weaves back and forth down the trail.

According to the passage, how are ants guided by trail pheromones?' 

Choose the option among A, B, C or D that best fits the blank space in the following passage: 

"The status of women’s rights today (1)….. dramatically in different countries and, in some cases, am ong groups within the same country, such as ethnic groups or economic classes.
 In recent decades women around the world have made strides in political participation. (2)….. the 1980s women could vote virtually everywhere in the world, except for a few Muslim countries. As of mid-2005, when women in Kuwait won suffrage, women could vote in all countries (3)…. Men could vote except Saudi Arabia. The right to vote usually included the right to (4)….. for elected office. In 2005 there were 12 female national leaders in the world, including 8 heads of (5)…… (3 monarchs and 5 presidents) and 4 heads of government (prime ministers). In 2005 women made (6)….. almost 16 percent of legislative bodies worldwide, compared to 11 percent in 1999 and 9 percent in 1987. Despite these advancements, women’s role in governmental decision-making remains (7) …...
 Many disparities persist between women’s legal rights and their economic status. Women today constitute nearly 70 percent of the world’s poor, (8) …..  international efforts to compensate women and men (9)…..  in the workplace. While women made up about 32 percent of the world’s labor force in 1990, the percentage of women in positions to make important decisions was far lower. In 2002 women held only 15.7 percent of corporate (10)…… positions in the 500 largest companies in the United States - an increase of 7 percentage points since 1995. In the mid-1990s women comprised only 1 percent of executives in the 1,000 largest corporations outside the United States."

3. As of mid-2005, when women in Kuwait won suffrage, women could vote in all countries (3)…. Men could vote except Saudi Arabia.

Rock carvings suggest that Stone Age people were hunting whales for food as early as 2,200 B.C. Such (31)______ hunting is still practised today in a number of societies including the Inuit people of Greenland and North America. Whaling became big (32)_____________ from the seventeenth century as the demand for whale bone and whale oil rose, and the humpback and sperm whales were hunted in increasing large number. (33)_________ just as stocks of these species began to fall, the explosive harpoon gun was invented. This weapon, together with the development of steam-powered ships, enable the whaler to hunt the fast moving fin and blue whales. In 1905, the whaling (34)____________ moved the water of Antarctica. The introduction of massive factory ships enabled the whales to be processed at sea. As a result, the blue whale had virtually disappeared by the 1950s. In 1946, The International Whaling Commision was established to maintain the declining whale populations. Quotas were set but these were often ignored and the numbers continued to fall. Hunting of many species continued until 1986 when the IWC finally responded to international (35)____________ and a band on commercial whaling was introduced.
(31).......................................

The handling and delivery of mail has always been a serious business, underpinned by the trust of the public in requiring timeliness, safety, and confidentiality. After early beginnings using horseback and stagecoach, and although cars and trucks later replaced stagecoaches and wagons, the Railway Mail Service still stands as one of America’s most resourceful and exciting postal innovations. This service began in 1832, but grew slowly until the Civil War. Then from 1862, by sorting the mail on board moving trains, the Post Office Department was able to decentralize its operations as railroads began to crisscross the nation on a regular basis, and speed up mail delivery. This service lasted until 1974. During peak decades of service, railway mail clerks handled 93% of all non-local mail and by 1905 the service had over 12,000 employees. 
Railway Post Office trains used a system of mail cranes to exchange mail at stations without stopping. As a train approached the crane, a clerk prepared the catcher arm which would then snatch the incoming mailbag in the blink of an eye. The clerk then booted out the outgoing mailbag. Experienced clerks were considered the elite of the Postal Service’s employees, and spoke with pride of making the switch at night with nothing but the curves and feel of the track to warn them of an upcoming catch. They also worked under the greatest pressure and their jobs were considered to be exhausting and dangerous. In addition to regular demands of their jobs they could find themselves the victims of train wrecks and robberies. 
As successful as it was, “mail-on-the-fly” still had its share of glitches. If they hoisted the train’s catcher arm too soon, they risked hitting switch targets, telegraph poles or semaphores, which would rip the catcher arm off the train. Too late, and they would miss an exchange. 

The word “glitches” in the third paragraph can be replaced by________. ' 

As many as one thousand years ago in the Southwest, the Hopi and Zuni Indians of North America were building with adobe-sun-baked brick plastered with mud.  Their homes looked remarkably like modern apartment houses. Some were four stories high and contained quarters for perhaps a thousand people, along with storerooms for grain and other goods. These buildings were usually put up against cliffs, both to make construction easier and for defense against enemies. They were really villages in themselves, as later Spanish explorers must have realised since they called them "pueblos", which is Spanish for towns. The people of the pueblos raised what are called "the three sisters" - corn,  beans, and squash. They made excellent pottery and wove marvelous baskets, some so fine that they could hold water. The Southwest has always been a dry country, where water is scarce. The Hopi and Zuni brought water from streams to their fields and gardens through irrigation ditches. Water was so important that it played a major role in their religion. They developed elaborate ceremonies and religious rituals to bring rain. The way of life of less - settled groups was simpler and more strongly influenced by nature.
Small tribes such as the Shoshone and Ute wandered the dry and mountainous lands between the Rocky Mountains and the Pacific Ocean. They gathered seeds and hunted small animals such as rabbits and snakes.
In the Far North, the ancestors of today's Inuit hunted seals, walruses, and the great whales. They lived right on the frozen season shelters called igloos built of blocks of packed snow. When summer came, they fished for salmon and hunted the lordly caribou.
The Cheyenne, Pawnee and Sioux tribes, known as the Plains Indians, lived on the grasslands between the Rocky Mountains and the Mississippi River. They hunted bison, commonly called the buffalo. Its meat was the chief food of these tribes, and its hide was used to make their clothing and the covering of their tents and tepees.

According to the passage, the Hopi and Zuni typically built their homes....................

Rock carvings suggest that Stone Age people were hunting whales for food as early as 2,200 B.C. Such (31)______ hunting is still practised today in a number of societies including the Inuit people of Greenland and North America. Whaling became big (32)_____________ from the seventeenth century as the demand for whale bone and whale oil rose, and the humpback and sperm whales were hunted in increasing large number. (33)_________ just as stocks of these species began to fall, the explosive harpoon gun was invented. This weapon, together with the development of steam-powered ships, enable the whaler to hunt the fast moving fin and blue whales. In 1905, the whaling (34)____________ moved the water of Antarctica. The introduction of massive factory ships enabled the whales to be processed at sea. As a result, the blue whale had virtually disappeared by the 1950s. In 1946, The International Whaling Commision was established to maintain the declining whale populations. Quotas were set but these were often ignored and the numbers continued to fall. Hunting of many species continued until 1986 when the IWC finally responded to international (35)____________ and a band on commercial whaling was introduced.
(35).......................................

Choose the option among  A, B, C or D that best answers the question about the passage:

"Since the 1940s, most international women’s rights efforts have been organized by the Commission on the Status of Women (CSW), an office established in 1947 by the United Nations (UN). The Commission is the only existing intergovernmental body that issues reports on and recommendations for the promotion of women’s political, social, economic, and cultural rights. The CSW also acts as an advocate for women’s rights and can urge immediate international action in cases of severe violations of women’s rights.
 The UN encouraged equality in the workplace for men and women when it sponsored the Convention Concerning Equal Remuneration for Men and Women Workers for Work of Equal Value in 1953 and the Convention Concerning Discrimination in Respect of Employment and Occupation in 1960. Over 100 countries ratified these measures. In 1975 the UN launched the Decade for Women, a ten-year effort to focus on women’s issues. From 1975 to 1985 international groups formed a series of conferences organized around the themes of equality, development, and peace. The conferences took place throughout the world and drew leaders and delegates from developing and industrialized nations alike. The Decade for Women culminated in the 1985 UN Nairobi Conference, held in Nairobi, Kenya, which was attended by 375 delegations of women from nations around the world.
 The United Nations’ Fourth World Conference on Women was held in Beijing, China, in 1995. Over 17,000 people registered for the event, including delegates from nearly 200 countries. The Platform for Action that emerged from the conference focused on the removal of obstacles to women’s equal participation in society. The most controversial sections of the platform concerned reproductive rights, particularly the right to have an abortion. The final document declared that “the ability of women to control their own fertility forms, an important basis for the enjoyment of other rights,” and asserted the right of women and men to have access to all legal methods of fertility regulation."

5. What was the conclusion of the Platform for Action on women’s reproductive rights?

Read the passage and choose the best answers. 
Until the 19th century, the denial of equal rights to women met with only occasional protest and drew little attention from most people. Because most women lacked the educational and economic resources that would enable them to challenge the prevailing social order, women generally accepted their inferior status as their only option. At this time, women shared these disadvantages with the majority of working class men, as many social, economic, and political rights were restricted to the wealthy elite.In the 19th century, as governments in Europe and North America began to draft new laws guaranteeing equality among men, significant numbers of women – and some men – began to demand that women be accorded equal rights as well.
At the same time, the Industrial Revolution in Europe and North America further divided the roles of men and women. Before the Industrial Revolution most people worked in farming or crafts-making, both of which took place in or near the home. Men and women usually divided the numerous tasks among themselves and their children. Industrialization led male workers to seek employment outside of the home in factories and other large-scale enterprises. The growing split between home and work reinforced the idea that women’s “rightful place” was in the home, while men belonged in the public world of employment and politics.
Organized efforts by women to achieve greater rights occurred in two major waves. The first wave began around the mid-19th century, when women in the United States and elsewhere campaigned to gain suffrage that is, the right to vote. This wave lasted until the 1920s, when several countries granted women suffrage

Until the 19th century, what was the status of the working class men in the society?

DISAPPEARING ALASKAN SEALS
On a winter afternoon, a dozen male Northern fur seals are on an island off south-western Alaska. To look at them, fighting for territory on the rocks, it’s hard to imagine that they are at the (27)____________of a baffling scientific mystery: why is this species beginning to disappear? These seals- which can weigh up to 270 kilograms-have an important and symbolic (28)_________in Alaska’s history. Their soft and luxurious fur, the coveted prize during the huge commercial sea harvests that were legal here in the Bering Sea through the early 20th century, was once so valuable it (29)_________Alaska’s economy. Starting in the 1950s, for reasons that are (30)_______because the harvests by then tended to be fairly small, the seal population began a slow decline . But lately it has been falling drastically, declining at an alarming (31)________of 6 per cent a year since 1998. From a (32)_________ of more than 2 million in Alaska in 1948, their numbers have fallen to about 1 million.
So (33)________, no one has been able to establish a precise cause for this, although theories (34)___________. The seals' food supply may be (35)________, or another species may be (36)________on the seals- perhaps killer whales, which no longer have as many great whales to eat because of harvesting of those mammals. Some people have suggested that the decline can be (37)______to entanglement in fishing nets ,but scientists say they doubt that this alone could (38)_________the recent population decline.
(36)....................................

Read the following passage and mark the letter A, B, C or D to indicate the correct answer for each of the blanks from 6 to 15

Revising for exams is not as easy as it looks. You will need to work out which routine suits you best, and then stick to it. Some people like studying at night when it’s quiet, whereas others find the early morning is a good time to get things done. You might enjoy (6)…….. to music while you revise, but this can be (7)……... Can you really concentrate (8)……….. two things at once? So think (9)……… you turn your radio on. Your (10)…….. is also important while you are revising. This may be a more than usually (11)………. period of your life, when you should take extra care to eat properly. No missed meals, or junk food, or (12)…….cups of coffee! Get plenty of exercise as well. If you have got fed up with (13)……. you’re doing, or find it hard to concentrate, go for a walk to clear your head. (14)……. exercise will help to keep your body fit and your brain working (15)………… Finally, you also need to take time off. Go out occasionally, see your friends, and make time to relax. Then you will return to your studies fresh and full of enthusiasm.

6...................

Read the following passage and mark the letter A, B, C or D on your answer sheet to indicate the correct answer to each of the following questions.

SCIENCE FLYING IN THE FACE OF GRAVITY

It looked just like another aircraft from the outside. The pilot told his young passengers that it was built in 1964, a Boeing KC-135 refueling tanker, based on the 707. But appearances were deceptive, and the 13 students from Europe and the USA who boarded the aircraft were in for the flight of their lives.

Inside, the area that normally had seats had become a long white tunnel. Heavily padded from floor to ceiling; it looked a bit like a lunatic asylum. There were almost no windows, but lights along the padded walls eerily illuminated it. Most of the seats had been taken out apart from a few at the back, where the young scientists quickly took their places with a look of apprehension.

From 12 months, science students from across the continents had competed to win a place on the flight at the invitation of the European Space Agency. The challenge had been to suggest imaginative experiments to be conducted in weightless conditions. For the next two hours the Boeing's flight resembled that of an enormous bird which had lost its reason, shooting upwards towards the heavens before hurting towards Earth. The intention was to achieve weightlessness for a few seconds.

The aircraft took off smoothly enough, but any feelings that I and the young scientists had that we were on anything like a scheduled passenger service were quickly dismissed when the pilot put the plane into a 45-degree climb which lasted around 20 seconds. Then the engine cut out and we became weightless. Everything became confused, and left or right, up or down no longer had any meaning. After 10 seconds of free-fall descent, the pilot pulled the aircraft out of its nosedive. The return of gravity was less immediate than its loss, but was still sudden enough to ensure that some students came down with a bump. After two hours of going up and down in the plane doing experiments, the predominant feeling was one of exhilaration rather than nausea. Most of the students thought it was an unforgettable experience and one they would be keen to repeat.

What does the word eerily in paragraph 2 mean?

DISAPPEARING ALASKAN SEALS
On a winter afternoon, a dozen male Northern fur seals are on an island off south-western Alaska. To look at them, fighting for territory on the rocks, it’s hard to imagine that they are at the (27)____________of a baffling scientific mystery: why is this species beginning to disappear? These seals- which can weigh up to 270 kilograms-have an important and symbolic (28)_________in Alaska’s history. Their soft and luxurious fur, the coveted prize during the huge commercial sea harvests that were legal here in the Bering Sea through the early 20th century, was once so valuable it (29)_________Alaska’s economy. Starting in the 1950s, for reasons that are (30)_______because the harvests by then tended to be fairly small, the seal population began a slow decline . But lately it has been falling drastically, declining at an alarming (31)________of 6 per cent a year since 1998. From a (32)_________ of more than 2 million in Alaska in 1948, their numbers have fallen to about 1 million.
So (33)________, no one has been able to establish a precise cause for this, although theories (34)___________. The seals' food supply may be (35)________, or another species may be (36)________on the seals- perhaps killer whales, which no longer have as many great whales to eat because of harvesting of those mammals. Some people have suggested that the decline can be (37)______to entanglement in fishing nets ,but scientists say they doubt that this alone could (38)_________the recent population decline.
(32)....................................

Rock carvings suggest that Stone Age people were hunting whales for food as early as 2,200 B.C. Such (31)______ hunting is still practised today in a number of societies including the Inuit people of Greenland and North America. Whaling became big (32)_____________ from the seventeenth century as the demand for whale bone and whale oil rose, and the humpback and sperm whales were hunted in increasing large number. (33)_________ just as stocks of these species began to fall, the explosive harpoon gun was invented. This weapon, together with the development of steam-powered ships, enable the whaler to hunt the fast moving fin and blue whales. In 1905, the whaling (34)____________ moved the water of Antarctica. The introduction of massive factory ships enabled the whales to be processed at sea. As a result, the blue whale had virtually disappeared by the 1950s. In 1946, The International Whaling Commision was established to maintain the declining whale populations. Quotas were set but these were often ignored and the numbers continued to fall. Hunting of many species continued until 1986 when the IWC finally responded to international (35)____________ and a band on commercial whaling was introduced.
(34).......................................

Why is it that flying to New York from London will leave you feeling less tired than flying to London from New York? The answer may be a clear case of biology not being able to keep up with technology.
Deep inside the brain there is a "clock" that governs every aspect of the body's functioning: sleep and wake cycles, levels of alertness, performance, mood, hormone levels, digestion, body temperature and so on. It regulates all of these functions on a 24-hour basis and is called the circadian clock (from the Latin, circa "about" + dies "day"). This body clock programmes us to be sleepy twice a day, between 3-5 a.m and again between 3-5 p.m.
Afternoon tea and siesta times are all cultural responses to our natural biological sleepiness in the afternoon.
One of the major causes of the travelers' malady known as jet lag is the non-alignment of a person's internal body clock with clocks in the external world. Crossing different time zones confuses the circadian clock, which then has to adjust to the new time and patterns of light and activity. To make matters more complex, not all internal body functions adjust at the same rate. So your sleep/wake may adjust to a new time zone at one rate, while your temperature adjusts at a different pace. Your digestion may be on a different schedule altogether.
Though we live in a 24-hour day, the natural tendency of the body clock is to extend our day beyond 24 hours. It is contrary to our biological programming to shrink our day. That is why traveling in a westward direction is more body-clock friendly than flying east. NASA studies of long haul pilots showed that westward travel was associated with significantly better sleep quantity and quality than eastward flights.
When flying west, you are "extending" your day, thus traveling in the natural direction of your internal clock. Flying eastward will involve "shrinking" or reducing your day and is in direct opposition to your internal clock's natural tendency. One of the more common complaints of travelers is that their sleep becomes disrupted. There are many reasons for this: Changing time zones and schedules, changing light and activity levels, trying to sleep when your body clock is programmed to be awake, disruption of the internal circadian clock and working longer hours.
Sleep loss, jet lag and fatigue can seriously affect our ability to function well. Judgment and decision-making can be reduced by 50%, attention by 75 percent, memory by 20 percent and communication by 30 percent.
It is often suggested that you adjust your watch as soon as you board a plane, supposedly to try to help you adjust to your destination's schedule as soon as you arrive. But it can take the body clock several days to several weeks to fully adjust to a new time zone.

Jet lag.........................