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. 
     The next time you are watching a film and you see one of the characters jumping out of a plane, falling off a horse, or being blown through a window - spare a (23) ______ for the stunt artist. Lots of people think that stunt artists are just "extras" who play small, unimportant parts in films and television. Nothing could be further from the truth. 
     A stunt artist must combine the skills of an actor with the physical abilities of a first- (24) _____________ athlete. He or she must be extremely fit, and highly trained in a number of activities like scuba-diving, horse riding, martial arts or parachuting. 
It is not easy to get started in a career as a stunt performer. Film and television producers look for experience and proven ability, as it is unlikely that they will take on a complete newcomer. However, because of the (25) ____________ of their profession, stunt artists tend to retire early. This means that new performers must be employed, or there will be no one to take (26) ______________ when the present generation quits. 
      Even when a stunt artist becomes well-known, the work is not regular. It may sometimes be necessary to travel to the other side of the world for a job which involves long hours and great physical danger. It is not a glamorous occupation either. Unlike the famous actors for (27) ____________ they sometimes risk their lives, few stunt artists are recognized in the street by adoring fans. 

 The next time you are watching a film and you see one of the characters jumping out of a plane, falling off a horse, or being blown through a window - spare a (23) ______ for the stunt artist

 

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

"Books which give instructions on how to do things are very popular in the United States today. Thousands of these How-to books are useful: in fact, there are about four thousand books with titles that begin with the words “How to”. One book, may tell you how to earn more money, another may tell you how to save or spend it, and another may explain how to give your money away.
 Many How-to books give advice on careers. They tell you how to choose a career and how to succeed in it. If you fail, however, you can buy the book “How to Turn Failure into Success”. If you would like to become very rich, you can buy the book “How to Make a Millionaire”. If you never make any money at all, you may need a book called “How to Live on Nothing”.
 One of the most popular types of books is one that helps you with personal problems. If you want to have a better love of life, you can read “How to Succeed in Love every Minute of Your Life”. If you tired of books on happiness, you may prefer books which give step-by-step instructions on how to redecorate or enlarge a house.
 Why have How-to books become so popular? Probably because life has become so complex. Today people have far more free time to use, more choices to make, and more problems to solve. How-to books help people deal with modern life."

4. Flow-to books appear only because …….

Read the following passage and mark A, B, C, or D to indicate the correct answer to each of the blanks from 46 to 50.
University researchers have taken samples from a preserved dodo specimen in an (46)         to uncover the extinct bird‟s family tree. They worked with the British Natural History Museum to collect and study genetic material from large number of specimens: a preserved dodo, the extinct solitaire bird, and 35 kind of living pigeons and doves. Their analysis (47)           the doo and the solitaire to be close relatives with the Nicobar pigeon, their nearest living relative. The dodo lived on Mauritius in the Indian Ocean. It was a flightless bird, bigger than a turkey. By 1681, all dodos had been (48)      by hungry sailors. The    solitaire, which looked a bit like a dodo, had gone the same way by 1800. By extracting short pieces of the dodo‟s DNA and (49)        these with the DNA of living birds, the scientists were able to deduce when the dodo evolved away from its relatives into a separate entity. The scientists can now (50)       assume that the dodo developed its distinctive appearance and features as a result of its geographical isolation. They are now convinced that it separated from the solitaire about 25 million years ago, long before Mauritius became an island.
(47).................

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 questions.

I’m standing on a sidewalk in the early morning. The great avenues of Paris are silent, and the shops are closed. Suddenly, a couple appeared from a hole in the sidewalk. Mud covers their boots. They place the iron cover over the hole and run down the street, smiling. The couple had been exploring the tunnels beneath the city.

When Romans occupied Paris, they cut down stone from deep within the earth to build their city. Later, the French used more stone to construct the Notre Dame Cathedral. This left huge underground tunnels upon which part of the city now. Once used for growing mushrooms and as a hiding place, today they are mostly forgotten, except by "cataphiles" - those who love to go down into the tunnels below Paris, even though it is actually not permitted.

In the 70s and 80s, it is easier to enter the tunnels because there were many more open entrances through forgotten doorways and into catacombs - rooms filled with bones. The bones had been moved into the tunnels to solve the problem crowded cemeteries. By the end of the 1980s, most of the entrances were shut and police regularly walked the tunnels. However, there are still cataphiles, like the couple I saw that morning, and for those who dare, the underground is an exciting place to meet, party, perform for each other or create art.

My own experience began beneath the old Paris opera house, where sewer workers showed me a 55-meter-long underground pond, a pond that actually had fish in it! Later, at France's national bank, officials guided me below to an amazing room filled with 2,600 tons of gold.

As cataphiles are the best guides, I then asked one of the cataphiles to give me a tour. Descending into the underground through a secret entrance beneath a bridge, we walked for hours through catacombs, and galleries of huge, bright paintings. The cataphile told me "Many people come down here to party, some to paint. Some people to destroy or to create or to explore. We do what we want, We don't have rules..."

(Adapted from Reading Explorer 2, Paul Macintyre&David Bohlke, 2015)

The word "here" in paragraph 5 refers to ...................

Read the following passage and mark the letter A, B, C or D on your answer sheet to indicate the correct word for each of the blanks from 36 to 40.
Vietnamese generally shake hands when greeting and parting. Using both hands shows respect as does a (36)_________ bow of the head. In rural areas, elderly people who do not extend their hand are greeted with a slight bow. Women are more likely to bow the head than to shake hands. Vietnamese names begin with the family name andare (37)_________ by a given name. People address one another by their given names,    but add a title that indicates their perceived relationship to the other person. These titles are family related rather than professional. Among colleagues, for example, the younger of the two might combine the given name with the title of - Anh(OlderBrother). A/n (38)_________ greeting combined with the given name and titleis “Xin chao” (Hello). Classifiers for gender and familiarity are also combined with the greeting. In formal meetings, business cards are sometimes exchanged on greeting.
Vietnamese have astrong (39)_________ of hospitality and feel embarrassed if they cannot show their guests  full respect by preparing for their arrival. Therefore, it is (40)_________ to visit someone without having been invited. Gifts are not required, but are appreciated. Flowers, incense, or tea may be appropriate gifts for the hosts. Hosts also appreciate a small gift for their children or elderly parents.
(36).................

Read the text below and decide which answer (A,B,C, or D) best fits each space.
Postsecondary institutions and private schools are corporations under U.S. law.  They are approved to operate as non-profit, for-profit, or public corporations (1)  _______ education and training. Increasingly, state authorities are requiring  approved educational providers to apply (2) _______ and receive accreditation  as a condition of final and continued approval. 
As corporate entities, U.S. institutions are internally self-governing and are (3)  _______ to make property, facilities, equipment, and utilities transactions; make  their own personnel decisions; decide whom to admit to study and to graduate;  (4) _______ their own funds from outside sources; enter into contracts and  compete for grants; and do most of the other things that corporations do.  Institutions compete (5) _______ one another for students, research funding,  faculty, and other benefits. Public institutions may compete within the same  state or territory for budget appropriations. It is the corporate nature of  institutions and the competition within the system that (6) _______ Americans  to refer to the concept of the educational or academic marketplace - an important distinctive element of the way U.S. education is organized. 
Some institutions are governed (7) _______ under multi-campus arrangements.  These include most local public schools (governed by school districts) and many  state community college and university systems. Whether single- or multi campus, institutional corporations (8) _______ by boards of citizens, both  alumni and non- alumni, who are ultimately responsible for all operations. They  appoint senior (9) _______, such as principals, headmasters, presidents, and  deans; and approve the actions taken (10) ______ their name. 

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

Read the text below and decide which answer (A,B,C, or D) best fits each space.
Tattooing is an old art. In ancient Greece, people who had tattoos were regarded  asmembers of the (16)____classes. On the other hand, tattooing was  (17)_____in Europe by the early Christians, who thought that it was a sinful  thing to(18) .It was not until the late 18th century, when Captain Cook  saw South Sea Islander decorating their bodies with tattoos that attitudes began  to change. Sailors came back from these islands with pictures of Christ on their  backs and from then on, tattooing (19)_____in popularity. A survey by the  French army in 1881 (20)_____that among the 387 men (21)_______ there were  1,333 designs. Nowadays, not everybody finds tattoos acceptable. Some people  thing that getting one is silly because tattoos are more or less permanent. There  is also some (22)_____about (23)_____ a blood disease from unsterilized needles. Even for those who do want a tattoo, the (24)_____of getting one is not  painless, but the final result, in their eyes, is (25)______the pain. 

19..........................

Read the passage below and choose one correct answer for each question.

Books which give instructions on how to do things are very popular in the United States today. Thousands of these How-to books are useful: in fact, there are about four thousand books with titles that begin with the words 'How-to". One book may tell you how to earn more money, another may tell you how to save or spend it and another may explain how to give your money away. Many How-to books give advice on careers. They tell you how to choose a career and how to succeed in it. If you fail, however, you can buy the book “How to Turn Failure into Success”. If you would like to become very rich, you can buy the book “How to Make a Millionaire”. If you never make any money at all. you may need abook called “How to Live on Nothing”. One of the most popular types of books is one that helps you with personal problems. If you want to have a better love of life, you can read “How to Succeed in Love Every Minute of Your Life”. If you are tired of books on happiness,  you may prefer books which give step-by-step instructions on how to redecorate or enlarge a house. Why have How-to books become so popular? Probably because life has become so complex. Today people have far more time to use, more choices to make, and more problems to solve. How-to books help people deal with modern life.

If you often read “How-to books”, you________. 

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 1 to 5.
Hospitality
Hospitality - looking after visitors - is universal but in different cultures hostsare (1)       to receive guests in different ways.
In much of the ancient world it was the custom to provide passing travellers with food and water. Today some old customs have (2)      . In a traditional Japanese household, if a guest admires a particular object in the house, the host will want to give it to the guest straight away. And in parts of Russia guests are greeted with bread and salt on a special cloth.The guest is (3)        to kiss them and hand them back to the host. Sometimes the guest breaks off a small piece of bread, dips it in the salt and eats it.
In some countries, when foreign guests arrive from abroad, they may feel they have been given a particularly (4)        meal. But this is probably because the host politely offers more and more food and drink and the guest is too embarrassed to (5)      anything down.
(3)....................

Read the following passage and mark the letter A, B, C or D on your answer sheet to indicate the correct word for each of the blanks from 36 to 40.
Vietnamese generally shake hands when greeting and parting. Using both hands shows respect as does a (36)_________ bow of the head. In rural areas, elderly people who do not extend their hand are greeted with a slight bow. Women are more likely to bow the head than to shake hands. Vietnamese names begin with the family name andare (37)_________ by a given name. People address one another by their given names,    but add a title that indicates their perceived relationship to the other person. These titles are family related rather than professional. Among colleagues, for example, the younger of the two might combine the given name with the title of - Anh(OlderBrother). A/n (38)_________ greeting combined with the given name and titleis “Xin chao” (Hello). Classifiers for gender and familiarity are also combined with the greeting. In formal meetings, business cards are sometimes exchanged on greeting.
Vietnamese have astrong (39)_________ of hospitality and feel embarrassed if they cannot show their guests  full respect by preparing for their arrival. Therefore, it is (40)_________ to visit someone without having been invited. Gifts are not required, but are appreciated. Flowers, incense, or tea may be appropriate gifts for the hosts. Hosts also appreciate a small gift for their children or elderly parents.
(40).................

Read the text below and decide which answer (A,B,C, or D) best fits each space.
Tattooing is an old art. In ancient Greece, people who had tattoos were regarded  asmembers of the (16)____classes. On the other hand, tattooing was  (17)_____in Europe by the early Christians, who thought that it was a sinful  thing to(18) .It was not until the late 18th century, when Captain Cook  saw South Sea Islander decorating their bodies with tattoos that attitudes began  to change. Sailors came back from these islands with pictures of Christ on their  backs and from then on, tattooing (19)_____in popularity. A survey by the  French army in 1881 (20)_____that among the 387 men (21)_______ there were  1,333 designs. Nowadays, not everybody finds tattoos acceptable. Some people  thing that getting one is silly because tattoos are more or less permanent. There  is also some (22)_____about (23)_____ a blood disease from unsterilized needles. Even for those who do want a tattoo, the (24)_____of getting one is not  painless, but the final result, in their eyes, is (25)______the pain. 

17....................

Read the text and choose the best answer (A, B, C or D) to each of the questions. 
Poles Apart
Many are surprised to learn that Antarctica is nearly twice the size of the United States. The name Antarctica was coined to mean "opposite to the Arctic." It is just that in many ways. Antarctica is a high, ice-covered landmass. In the Arctic the landmasses are grouped around the ice-covered Arctic Ocean.
Largely because of this difference, the climate of the two areas is very different. Antarctica is the coldest area in the world. On the average it is about 30 degrees colder than the Arctic. At the South Pole, nearly 10.000 feet high, monthly mean temperatures run well below zero. Only in coastal regions do temperatures sometimes rise about freezing in the summer (December to March). In contrast, near the North Pole monthly mean temperatures often rise above freezing. 
At both poles, daily temperatures may drop far below the monthly mean. At the American South Pole Station, winter temperatures sometimes fall below -100 degrees Fahrenheit. Elsewhere, on higher parts of the south polar plateau, even lower temperatures are recorded.
A temperature of -127 degrees Fahrenheit was measured in August 1960. It is the world's record low temperature.
Partly because of this climatic difference, the land animals and plants of the two regions are very different. On the continent of Antarctica, there are very few plants. In the Arctic there are many plants. In some of the few ice-free areas of Antarctica, mosses, lichens, and algae are found. Penguins populate Antarctic coastlines but do not exist in the Arctic. The land animals of the Arctic are foxes, bears, reindeer, and lemmings. These animals are unknown in the Antarctic. Old rock layers show that this "oppositeness" between north and south extends far back into the early chapters of earth history.
Ice is the great feature of Antarctica. More than 4.5 million square miles of ice sheet cover the area. Great rivers of ice, called glaciers, push down the mountains. Antarctica is the storehouse of about 85 percent of the total world supply of ice. 
The icecap is very thick, averaging nearly 8,000 feet. At one spot, scientists have found the distance from the surface to the rock underneath the ice to be more than 13,000 feet.
If this great volume of ice were to melt, the volume of the world oceans would increase, and sea level would rise. Extreme atmospheric changes would have to take place for this to happen.

 One type of animal found in the Arctic is the _________.

Read the text below and decide which answer (A,B,C, or D) best fits each space.
Statesmen define a family as ―a group of indivi duals having a commo n  dwelling andrelated by blood, adoption or marriage, (1) includes common law relationships.‖ Most people are born into one of these groups and (2) live their lives as a family in such a group.Although the definition of a  family may not change, (3).relationship of people to each other within the family  group changes as society changes. More and more wives are (4) paying jobs,  and, as a result, the roles of husband, wife and children are changing. Today,  men expect to(5) . for pay for about 40 years of their lives, and, in today‘s  marriages(6) . which both spouses have paying jobs, women can expect to  work for about 30 to 35 years of their lives. This mean that man must learn to do  their share of family tasks such as caring for the children and daily (7) chores.  Children, too, especially adolescents, have to (8) with the members od their  family in sharing household tasks. The widespread acceptance of contraception  has meant that having (9) is as matter of choice, not an automatic result of  marriage. Marriage itself has become a choice. As alternatives (10)  common-law relationships and single-parent families have become socially  acceptable, women will become more independent. 

3...........................

Read the following passage and choose the best answer for each blank.

AUDIOBOOKS - BOOKS ON CASSETTE

In the modern world, there is a wealth of leisure activities to choose from. Entertainment industries (26)________ for your leisure time. You can watch TV, listen to music, go to an art gallery or concert or, of course, read a book. Sometimes it seems that reading is (27)________because, even if you're a fast reader, it can take a (28)________amount of time to finish a novel, for example. But in the (29)________world, time is something that can be in short supply. Book publishers haven't been (30)________to realise this and are now selling a product which needn't (31)________as much of your time but still tells you an excellent story. The new product is the audiobook -cassette recordings of shortened novels, often read by well-known personalities or the authors themselves. Audiobooks are (32)________new but people are becoming more aware of them and sales are increasing all the time. One of the attractions of audiobooks is that they're (33)________listening to the radio. You can listen to what you want when you want, and you won't ever (34)________anything. Much of their appeal lies in their flexibility. They (35)________you to do other things while you're listening, such as driving or doing the housework. For some people, audiobooks can be a much more enjoyable way of gaining knowledge than reading.

(35)________

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 26 to 30.
The position of sport in today‟s society has changed out of all regconition. People no longer seem to think of sport as “just a game” – to be watched or played for the (21)_________ of enjoyment. Instead, it has become big business worldwide. It has become accepted practice for loading companies to provide sponsorship. TV companies pay large sums of money to screen important matches or competitions. The result has been huge financial rewards for athletes, some of (22)_________ are now very wealthy, particularly top footballers, golfers and tennis players. (23)_________ , it is not unusual for some athletes to receive large fees on top of their salary, for advertising products or making personal appearances.
A trend towards shorter working hours means that people generally tend to have more free time, both to watch and to take part in sporting activity; sport has become a significant part of the recreation industry that we now rely (24)_________ to fill our leisure hours. Professional sport is a vital part of that industry, providing pleasure for millions of (25)_________ people all over the world.
(24).................

Read the following the passage and mark the letter A, B, C or D on your answer sheet to indicate the correct word or phrasethat best fits each of the numbered blanks from 31 to 35.
From the next year, every student in their final rear at our school will study for a compulsory Diploma of Practical Achievement. This will be in addition to the normal examinations. Up to now, the course has been optional, but from now on every student must (31)        it.
The aim is to (32)   students with "life skills", which the Diploma divides into eight categories. These cover a range of things relevant to life beyond school, from sending an e-mail to giving presentation  to  an  audience.  Under  the  heading     "survival",  (33)      ,  students   can learn  car mainternance, first aid and cooking. We have discovered that many students cannot do simple things such as mend a puncture or boil an egg. At the other extreme, the Diploma includes such things as how to design a webpage and how to cope if someone has a heart attack. It has been called a " Diploma in Common Sense".
On the course, students will not be taught in the traditional (34)  
  , but rather will be guided and encouraged to do things for themselves. This is above all a practical "hand-on" course. To a greater or lesser extent, good schools have always tried to (35)        these skills. Unfortunately, students have not always shown much interest because such skills are not directly related to passing exams for higher education. We hope this will change now that we have a proper course that will lead to a recognised diploma.
(35)..................

Read the following passage and choose the best answer for each blank.

AUDIOBOOKS - BOOKS ON CASSETTE

In the modern world, there is a wealth of leisure activities to choose from. Entertainment industries (26)________ for your leisure time. You can watch TV, listen to music, go to an art gallery or concert or, of course, read a book. Sometimes it seems that reading is (27)________because, even if you're a fast reader, it can take a (28)________amount of time to finish a novel, for example. But in the (29)________world, time is something that can be in short supply. Book publishers haven't been (30)________to realise this and are now selling a product which needn't (31)________as much of your time but still tells you an excellent story. The new product is the audiobook -cassette recordings of shortened novels, often read by well-known personalities or the authors themselves. Audiobooks are (32)________new but people are becoming more aware of them and sales are increasing all the time. One of the attractions of audiobooks is that they're (33)________listening to the radio. You can listen to what you want when you want, and you won't ever (34)________anything. Much of their appeal lies in their flexibility. They (35)________you to do other things while you're listening, such as driving or doing the housework. For some people, audiobooks can be a much more enjoyable way of gaining knowledge than reading.

(26)________

In “Cerealizing America”, Scott Bruce and Bill Crawford remark that the cereal  industry uses 816 million pounds of sugar per year. Americans buy 2.7 billion  packages of breakfast cereal each year. If (1) _______ end to end, the empty  cereal boxes from one year's consumption would (2) _______ to the moon and back. One point three (1.3) million advertisements for cereal are broadcast on  American television every year at a(n) (3) _______ of $762 million for airtime.  Only automobile manufacturers spend more money on television advertising  than the makers of breakfast cereal. (4) _______ of the boxed cereals found in  supermarkets contain large amounts of sugar and some contain more than 50%  sugar. Cereal manufacturers are very clever in their marketing, making many  cereals appear much healthier than they really are by “fortifying” them with vitamins and minerals. Oh, (5) ______ – you now have vitamin-fortified sugar! Before you eat any cereal, read the ingredient list and see how (6) _______  sugar appears on the ingredient list. Then check the “Nutrition facts” panel. 
There are actually only a small handful of national commercially-branded cereals  that are made (7) _______ whole grains and are sugar-free. If you shop at a health  food store instead of your local supermarket, you (8) _______ to find a healthy,  whole grain, sugar-free (or very low sugar) cereal. But (9) _______! Some of the  health food store boxed cereals are sweetened with fruit juice or fructose.  Although this may be an improvement (10) _______ refined white sugar, this can  really skyrocket the calories. 

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

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 questions.

   Marianne Moore (1887-1972) once said that her writing could be called poetry only because there was no other name for it. Indeed her poems appear to be extremely compressed essays that happen to be printed in jagged lines on the page. Her subjects were varied: animals, laborers, artists, and the craft of poetry. From her general reading came quotations that she found striking or insightful. She included these in her poems, scrupulously enclosed in quotation marks, and sometimes identified in footnotes. Of this practice, she wrote, "Why many quotation marks?" I am asked ... When a thing has been so well that it could not be said better, why paraphrase it? Hence, my writing is, if not a cabinet of fossils, a kind of collection of flies in amber." Close observation and concentration on detail and the methods of her poetry.

   Marianne Moore grew up in Kirkwood, Missouri, near St. Lois. After graduation from Bryn Mawr College in 1909, she taught commercial subjects at the Indian School in Carlisle, Pennsylvania. Later she became a librarian in New York City. During the 1920’s she was editor of

   The Dial, an important literary magazine of the period. She lived quietly all her life, mostly in Brooklyn, New York. She spent a lot of time at the Bronx Zoo, fascinated by animals. Her admiration of the Brooklyn Dodgers-before the team moved to Los Angeles-was widely known.

   Her first book of poems was published in London in 1921 by a group of friends associated with the Imagist movement. From that time on her poetry has been read with interest by succeeding generations of poets and readers. In 1952 she was awarded the Pulitzer Prize for her Collected Poems. She wrote that she did not write poetry for money or fame. To earn a living is needful, but it can be done in routine ways. One writes because one has a burning desire to objectify what it is indispensable to one's happiness to express.

The word "it" refers to ______.

Light from a living plant or animal is called bioluminescence, or cold light, to distinguish it from incandescence or heat-generating light. Life forms could not produce incandescent light without being burned. Their light is produced in chemicals combining in such a way that little or no measurable heat is produced, and the life forms generating it are unharmed. Although bioluminescence is a relatively complicated process, it can be reduced to simple terms. Living light occurs when luciferin and oxygen combine in the presence of luciferase. In a few cases, fireflies the most common, an additional compound called ATP is required.
The earliest recorded experiments with bioluminescence in the late 1800s are attributed to Raphael Dubois, who extracted a luminous fluid from a clam, observing that it continued to glow in the test tube for several minutes. He named the substance luciferin, which means “the bearer of life”. In further research, Dubois discovered that several chemicals were required for bioluminescence to occur. In his notes, it was recorded that a second important substance, which he called luciferase, was always present. In later study of small, luminous sea creatures, Newton Harley concluded that luciferin was composed of carbon, hydrosen, and oxygen, which are the building blocks of all living cells. He also proved that there are a variety of luciferin and luciferase, specific to the plants and animals that produce them.
Much remains unknown, but many scientists who are studying bioluminescence now believe that the origin of the phenomenon may be traced to a time when there was no oxygen in the Earth’s atmosphere. When oxygen was gradually introduced to the atmosphere, it was actually poisonous to life forms, plants and animals produced light to use up the oxygen in a gradual but necessary adaptation. It is speculated that millions of years ago, all life may have produced light to survive. As the millennia passed, life forms on Earth became tolerant of, and finally dependent on oxygen, and the adaptation that produced bioluminescence was no longer necessary, but some primitive plants and animals continued to use the light for new functions such as mating or attracting prey.

The word “it” refers to:

Read the following passage and choose the correct answer to each of the questions.

The word "robot" first appeared in a 1921 stage play by Czech writer Karel Capek. In the play, a man makes a machine that can think, which he calls a robot and which ends up killing its owner. In the 1940s, the American science fiction writer, Isaac Asimov, wrote a series of stories about robots and invented the term 'robotics', the science of robots. Meanwhile, in the real world, the first robots were developed by an engineer, Joseph F. Engelberger, and an inventor, George C. Devol. Together they started Unimation, a manufacturing company that produced the first real robot in 1961, called the Unimate. Robots of this type were installed at a General Motors automobile plant and proved to be a success. They worked reliably and saved money for General Motors, so other companies were soon acquiring robots as well.

These industrial robots were nothing like the terrifying creatures that can often be seen in science fiction films. In fact, these robots looked and behaved nothing like humans. They were simply pieces of computer-controlled machines, with metal "arms" or "hands". Since they were made of metal, they could perform certain jobs that were difficult or dangerous for humans, particularly jobs that involve high heat. And since robots were tireless and never got hungry, sleepy, or distracted, they were useful for tasks that would be tiring or boring for humans. Industrial robots have been improved over the years, and today they are used in many factories around the world. Though the use of robots has meant the loss of some jobs, at the same time other jobs have been created in the design, development, and production of the robots.

Outside of industry, robots have also been developed and put into use by governments and scientists in situations where humans might be in danger. For example, they can be sent in to investigate an unexploded bomb or an accident at a nuclear power plant. Researchers also use robots to collect samples of hot rocks or gases in active volcanoes. In space exploration, robots have performed many key tasks where humans could not be present, such as on the surface of Mars. In 2004, two robotic Rovers, small six-wheeled computerized cars, were sent to Mars.

What does the word they in paragraph 2 refer to?