That little "a" with a circle curling around it that is found in E - mail addresses is most commonly referred to as the "at" symbol. Surprisingly though, there is no official, universal name for this sign. There are dozens of strange terms to describe the "@" symbol. Before it became the standard symbol for electronic mail, the "@" symbol was used to represent the cost of something or how heavy something is. For instance, if you purchased 6 apples, you might write it as 6 apples "@" $1.10 each. With the introduction of e-mail came the popularity of the "@" symbol. The "@" symbol or the "at sign" separates a person's online user name from his mail server  address. For instance, joe@uselessknowledge.com. Its widespread use on the Internet made it necessary to put this symbol on keyboards in other countries that have never seen or used the symbol before. As a result, there is really no official name for this symbol. The actual origin of the symbol remains a mystery. History tells us that the @ symbol came from the tired hands of the Middle Ages. During the Middle Ages before the invention of printing machines, every letter of a word had to be copied with great efforts by hand for each copy of a published book. The monks that performed these long, boring coping duties looked for ways to reduce the number of individual strokes   per word for common words. Although the word "at" is quite short to begin with, it was a common enough word in text and documents so that those monks thought it would be quicker and easier to shorten the word "at" even more. As a result, the monks changed the shape of "t" into a circle to surround "a", thus leaving out two strokes in the spelling "t". Which of the following is the best title of the passage? A) How "at" developed into @. B) How @ came into being. C) How monks invented @. D) How people wrote the cost of something.
B

Poor Oral Health Leads to Social and Emotional Problems A new report says nearly four-billion people have major tooth decay, or cavities. That number represents more than half of the world's population. Health officials are warning that failure to repair cavities can lead to social and emotional problems. Wagner Marcenes is with the Institute of Dentistry at Queen Mary, University of London. He led a team of researchers as part of the Global Burden of Disease 2010 study. About 500 researchers attempt to collect and examine studies about all major diseases. They used the information to estimate rates of the infection. The report says untreated tooth decay is the most common of all 291 major diseases and injuries. Professor Marcenes says cavities or holes  in permanent teeth are also known as caries. "Caries is a chronic disease that shares the same risk factors as cancer, cardiovascular disease. What we're having now is an increase in disease from highly developed countries happening in sub-Saharan Africa and probably it will be in other areas of Africa, too." He says an increase in tooth decay in Africa could be a result of developing countries becoming more like Western nations. "It is likely to be related to a change in diet. Our industrialized diet leads to chronic disease, which includes caries. And that may be the main explanation." Western diets are rich in sugar, a leading cause of health problems in the mouth. Wagner Marcenes says oral health problems can have a major effect on a person's quality of life. First, cavities make eating difficult. Second, people may change what they eat. They may eat softer foods that are not hard to chew. However, softer foods are often fattier foods. But professor Marcenes says the biggest issue in tooth decay is both social and mental. He says the researchers found strong evidence that the mouth has a big influence on socialization. He says many people want to hide bad teeth. They smile less and communicate less. Wagner Marcenes is calling for an "urgent, organized,... What is the writer's attitude towards tooth decay? A) indifferent B) concerned C) angry D) negative
B

Have you ever felt annoyed when left talking to yourself after your mobile phone battery runs out in the middle of a call? If yes, then here comes some good news. Scientists are now perfecting a way to recharge electrical equipment while on the move.     Researchers from theprefix = st1 /Netherlands,FranceandPortugalannounced last week that they have developed very thin solar panels that can be put on clothes. They can also be added to furniture and rooftops. They change light from the sun into electricity.     In about three years, you'll be able to wear a jacket that will recharge your phone as you walk. For camping fans, the development could lead to a tent which charges batteries all day so you can have light or music at night.     The basic technology of wearable solar panels is the same as that used for traditional solar panels. Pairs of sheets of semi-conducting silicon   are linked together to form the panel. But scientists made them much thinner by using different silicon. At one micrometre, they are of the same thickness as photographic film.     "This technology will make it easier for people to use clean energy sources," said a physicist in theNetherlandswho led the team of scientists. But the thin panels are not as efficient as the thicker ones. While some solar panels now operate at an efficiency of about 20 per cent, the new flexible   panels are only 7 per cent efficient. But the thinner panel is cheaper. An A4 sized panel put onto the back of a jacket cost less than US$13. It could charge a cellphone during a summer walk in the countryside. As long as you stay within range of the transmitting masts   that relay a call to the networks, phones will never again run out of power. Which of the following is TRUE about the electrical equipment? A) It can only be used while camping. B) You can listen to some music on it. C) It will be put into use in a few years. D) It can only be used as you walk.

C