The ability to conduct electricity is one of the key properties of a metal. Other solid material such as silicon can conduct electricity but only effectively at certain temperatures. Also, some substances such as salt (sodium chloride) can conduct when molten or when dissolved in water. The ability of metals to conduct electricity is due to how their atoms bond together. In order to bond together the metal atoms lose at least one of their outermost electrons. This leaves the metal atoms with a positive charge and they are now strictly ions. The lost electrons are free to move in what are known as a sea of electrons. Since the electrons are negatively charged they attract the ions and this is what keeps the structure together.

An electric current is a flow of charge and since the electrons in the sea of electrons are free to move they can be made to flow in one direction when a source of electrical energy such as a battery is connected to the metal. Hence we have an electric current flowing through the wire, and this is what makes metals such good conductors of electricity. The only other common solid conducting material that pencil users are likely to encounter is graphite (what the 'lead' of a pencil is made from). Graphite is a form of carbon and again the carbon atoms bond in such a way that there is a sea of electrons that can be made to flow as an electric current. Likewise, if we have an ionic substance like salt we can make the electrically charged ions flow to create a current but only when those ions are free to move, either when the substance is a liquid or dissolved in water. In its solid state an ionic substance like salt cannot conduct electricity as its charged ions cannot flow.

Electrical insulators are substances that cannot conduct electricity well either, because they contain no charged particles or any charged particles they might contain do not flow easily. Water itself is a poor conductor or electricity as it does not contain a significant amount of fully charged particles (the ends of a water molecule are partly charged but overall the molecule is neutral). However, most water we encounter does contain dissolved charged particles, so it will be more conductive than pure water. Many of the problems that occur when touching electrical devices with wet hands result from the ever-present salt that is left on our skin through perspiration and it dissolves in the water to make it more conductive.

According to the passage, a metal can conduct electricity due to________.

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John was reading a book when I ____ him.

The children seem to be totally .............................. of working quietly by themselves.

(529)_______

Choose the best answer:
free/ He/ most/ time/ sports/ spends/ of/ his/ playing

Choose the sentence A, B, C or D which in closest in meaning to the printed sentence.:
The demand was so great. They had to reprint the book immediately.

Choose the best answer:
She had never imagined being able to visit such _____ countries.

Read the reading below carefully, and then complete it with the best option A, B, C or D given below:
Carefully conducted studies that have followed the children of working mothers have not been able to show any long-­‐term problems, compared (1)_____children whose mothers stay at home. My personal (2) _____is that mothers should be allowed to work if they wish. Whether we like it or not, there are a number of mothers who just have to work. There are many who must work out of pure economic (3) _____. Many mothers are not born to be full-time parents. After a few months at home with a much loved infant, the feel trapped and isolated. There are a number of options when it refers to choosing childcare. These range from child minders and nannies through to Granny or the kind of lady across the street. In reality, (4) _____ many parents do no have any choice; they have to accept anything they can get. Be prepared! No (5)_____ how good the children may be, some children are going to protect wildly if they are left. This is a (6) _____ normal stage of child development. Babies separate well in the first six months, but soon after that they start to get a crush on Mum and close family (7)_____. Make sure that in the first week, you allow plenty of time to help your child (8)_____. All children are different. Some are independent,(9) _____ others are more attached to their mothers. Remember that if you want to do the best for your children, it’s not the quantity of time you spend with them, it’s the (10)_____ that matters

Read the reading below carefully, and then complete it with the best option A, B, C or D given below:
Other disabilities include hearing, visual, or orthopedic impairments; autism; (1) _______ traumatic brain injury. An increasing number of children in the United States are identified as having attention-deficit hyperactivity disorder (ADHD) and (2) _______ special education services. Many schools in the United States provide special education services (3) _______ gifted children, although federal law does not mandate these services. Gifted children demonstrate (4) _______ high abilities in intellectual, creative, academic, leadership, or artistic areas. Estimates of the gifted (5) _______ in the United States range from 3 to 5 percent of all schoolchildren.

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A large number of jellyfish are _________ stake due to overhunting.

Read the following passage and choose the best answer (A, B, C, D):
The ubiquitous bar code, developed more than twenty years ago, is not a stagnant product. On the contrary, the technology has been improved so that it can be used more efficiently. Much less expensive than a computer chip, the bar code can hold more information than it had in the past by adding a second dimension to the structure. The bar code consists of a series of parallel vertical bars or lines of two different widths, although sometimes four widths are used, printed in black on a white background. Barcodes are used for entering data into a computer system. The bars represent the binary digits 0 and 1, just like basic computer language, and sequences of these digits can indicate the numbers from 0 to 9, which can then be read by an optical laser scanner and processed by a digital computer. Arabic numbers appear below the code. The traditional bar code has been used to monitor skiers at ski lifts and to determine price and perform inventory control on groceries, drugs, medical supplies, manufactured parts, and library books to name a few. The bar code used on grocery products, introduced in the 1970s, is called a universal product code (or UPC) and assigns each type of food or grocery product a unique code. The five digits on the left are assigned to a particular manufacturer or maker and the five digits on the right are used by that manufacturer to identify a specific type or mark of product. Traditional single dimension bar codes are not readily customizable because there is little extra space. The two-dimensional bar code, with an information density of 1,100 bytes, allows a considerably greater amount of information to be coded than does the traditional bar code, including customized information. [A] It also has built-in redundancy, meaning that the identical information is duplicated on the same code. [B] Therefore, if the code is damaged, it can still be read. [C] The technology even allows pictures or texts to be contained within the code, as well as bar code encryption. [D] The new technology dramatically reduces the errors of the single dimensional bar code and reduces the enormous costs that some companies have reported in the past. 
3. The author implies that the bar code: 

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:
There are three valid arguments to support the preservation of endangered species. Aesthetic justification contends that biodiversity contributes to the quality of life because many of the endangered plants and animals are particularly appreciated for their unique physical beauty. The aesthetic role of nature in all its diverse forms is reflected in the art and literature of every culture attaining symbolic status in the spiritual life of many groups. According to the proponents of the aesthetic argument, people need nature in all its diverse and beautiful forms as part of the experience of the world.
Another argument that has been put forward, especially by groups in the medical and pharmacological fields, is that of ecological self-interest. By preserving all species, we retain a balance of nature that is ultimately beneficial to humankind. Recent research on global ecosystems has been cited as evidence that every species contributes important or even essential functions that may be necessary to the survival of our own species. Some advocates of the ecological argument contend that important chemical compounds derived from rare plants may contain the key to a cure for one of the diseases currently threatening human beings. If we do not protect other species, then they cannot protect us.
Apart from human advantage in both the aesthetic and ecological arguments, the proponents of a moral justification contend that all species have the right to exist, a viewpoint stated in the United Nations World Charter for Nature, created in 1982. Furthermore, if humankind views itself as the stewards of all the creatures on Earth, then it is incumbent upon human beings to protect them, and to ensure the continued existence of all species. Moral justification has been extended by a movement called “deep ecology,” the members of which rank the biosphere higher than people because the continuation of life depends on this larger perspective. To carry their argument to its logical conclusion, all choices must be made for the biosphere, not for people.

Which of the following is the main topic of the passage?

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They will never forget _______ the man-eating shark at the beach.

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:
Of all modern instruments, the violin is apparently one of the simplest. It consists in essence of a hollow, varnished wooden sound box, or resonator, and a long neck covered with a fingerboard, along which four strings are stretched at high tension. The beauty of design, shape, and decoration is no accident. The proportions of the instrument are determined almost entirely by acoustical; considerations. Its simplicity of appearance is deceptive. About 70 parts are involved in the construction of a violin. Its tone and its outstanding range of expressiveness make it an ideal solo instrument. No less important, however, is its role as an orchestral and chamber instrument. In combination with the larger and deeper-sounding members of the same family, the violins form the nucleus of the modern symphony orchestra.
The violin has been in existence since about 1550. Its importance as an instrument in its own right dates from the early 1600’s, when it first became standard in Italian opera orchestras. Its stature as an orchestral instrument was raised further when in 1626 Louis XIII of France established at his court the orchestra known as Les vinq-quatre violons du Roy (The King’s 24 Violins), which was to become widely famous later in the century.
In its early history, the violin had a dull and rather quiet tone resulting from the fact that the strings were thick and were attached to the body of the instrument very loosely. During the eighteenth and nineteenth century, exciting technical changes were inspired by such composer- violinists as Vivaldi and Tartini. Their instrumental compositions demanded a fuller, clearer, and more brilliant tone that was produced by using thinner strings and a far higher string tension. Small changes had to be made to the violin’s internal structure and to the fingerboard so that they could withstand the extra strain. Accordingly, a higher standard of performance was achieved, in terms of both facility and interpretation. Left-hand technique was considerably elaborated, and new fingering patterns on the fingerboard were developed for very high notes.

What is the main idea presented in paragraph 3?

Read the following passage and mark the letter A, B, C, or D to indicate the correct answer to each of the questions form 31 -35

Tourism will always have an impact on the places visited. Sometimes the impact is good, but often it is negative. For example, if lots of people visit one place, then this can damage the environment. The question is - how can we minimize the problems without preventing people from travelling and visiting places? 

The main aim of ecotourism is to reduce the negative impact that tourism has on the environment and local people. The idea is to encourage tourists to think about what they do when they visit a place. 

It's great to talk about protecting the environment, but how do you actually do this? There are a number of key points. Tourists shouldn't drop litter, they should stay on the paths, they shouldn't interfere with wildlife and they should respect local customs and traditions. 

Some people see ecotourism as a contradiction. They say that any tourism needs infrastructure - roads, airports and hotels.The more tourists that visit a place, the more of these are needed and, by building more of these, you can't avoid damaging the environment. 

But, of course, things aren't so black and white. Living in a place of natural beauty doesn't mean that you shouldn't benefit from things like better roads. As long as the improvements benefit the local people and not just the tourists, and the local communities are consulted on plans and changes, then is there really a problem? 

In 2002 the United Nations celebrated the "International Year of Ecotourism". Over the past twenty years, more and more people have started taking eco-holidays. In countries such as Ecuador, Nepal, Costa Rica and Kenya, ecotourism represents a significant proportion of the tourist industry. 

According to the passage, what does the ecotourism aim at

Which subject is this book _____?

(378)________

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 :
The beautiful white bears found in the Arctic are in grave danger, and human beings are very (1) _______ the cause of this danger. As we bum fossil fuels to generate electricity or get us around town in our cars and trucks. We create a massive amount of carbon dioxide. This gas has increased in (2) _______. so much over the past few centuries that it is causing global warming. Polar bears need sea ice in order to live because this ice is their hunting (3) _______, The bears’ main source of food is the meat and blubber of seals. These animals come to the surface holes in the ice to breathe. It is there that the polar bears have (4) _______to ambush the seals. Without any ice, there is nowhere for the bears to stalk their prey. The seals rarely venture onto land and spend their time out on the sea ice. In recent years, the sea ice has disappeared in the Arctic during the late summer. This is dangerous for the polar bears, as they rely almost exclusively on seals for food. (5) _______ brown and black bears, polar bears do not hibernate during the winter.

Choose the best answer:
We are going to have a picnic _____________ the bad weather.

Read the passage below carefully, and then choose the best answer:
Clean and Popular
Wind power is a very clean source of energy. This is how wind power works. Wind makes windmills spin. When the windmills spin, they make electricity. Then we can use the electricity. Many people think that wind power is new, but that is not true. For thousands of years, people have used wind to sail boats and move water. We still do those things today, but these days we mostly use wind power to make electricity. Wind power is a very popular source of energy. Most people think that should use it more and more. First of all, it is clean. Windmills don’t pollute the environment at all. Second, we can use wind power forever. After all, we will always have wind. In addition, wind power is cheap, and it is getting even cheaper. A lot of people don’t understand wind power very well. They believe that there are problems with wind power, but many of those problems are not real. For example, some people say that windmills are dangerous for birds. That used to be true, but it isn’t true anymore. Old windmills killed birds because they spun very fast. New windmills spin slowly, and they aren’t dangerous for birds. However, there are real problems with windmills. One problem is that many people think windmills are very ugly. This is a problem for some people, because windmills are often in very pretty areas. Besides, wind doesn’t blow all the time, so we can’t use wind power all year round. Finally, windmills are noisy. Wind power is becoming more and more common. Right now, more than 80 countries use wind power. About 2.5 percent of the world’s power comes from the wind. For some countries, that number is a lot higher. Wind power gives Denmark more than 25 percent of its electricity.
6. Why don’t new windmills kill birds?

Read the reading below carefully, and then complete it with the best option A, B, C or D given below:
Azmah, Inc., Hits a Record
1 May - Azmah, lnc., one of Malaysia's leading electronics manufacturers, announced yesterday that it achieved record safes in the last quarter. Azmah's revenue jumped 18 percent to RM 144 million, with the increase largely (1)------- by television sales. Sales of flat-screen models alone rose nearly 30 percent over sales figures from the previous quarter. (2)-------, production costs also reached record highs. Azmah reports its profit margins have been reduced by 20 percent because of the rising prices of computer chips and other electronic (3)------

Rewrite sentences without changing the meaning
He prefers siting at home to playing outside.

Mark the letter A, B, C, or D to indicate the word or phrase that is CLOSEST in meaning to the underlined part in each of the following questions.
There has been a significant increase in the number of crimes reported this year