Microwaves may be great at warming up food, but what about warming people? Using microwaves to directly heat owners of a room would save much of the energy wasted by heating walls and furniture. And despite popular ideas about microwaves, this technique would be safe, according to Charles R. Burlier of the Microwave Research Center in Marlborough, New Hampshire. Low-power microwaves only penetrate the skin (low-power microwave penetration in a ham is about 0.2 inches, for example) and with no negative effects. To test this idea, Buffler subjected himself to microwaves in a special room using a standard 500-watt, 2459 MHz magnetron . He found that a person will start to feel warmth at about 20 milliwatts per square centimeter (mw. / sq. cm. ) ; a satisfactory feeling of warmth occurs between 35 and 50mw. / sq. cm. By comparison, a person standing in noonday summer sun feels the amount of 85 mw. / sq. cm. And a frozen meat pie in your microwave oven receives about 1000 mw. / sq. cm. In houses of the future, each room could be provided with its own magnetron, says Buffler. When you stepped into the living room, for example, a motion detector would turn on the magnetron, filling the room with low-power microwaves. In the same way that a microwave oven heats up a hamburger, but not the plate it's on, you would feel warmth from the microwaves without changing the temperature of your coffee table. (You could, however, make your favorite easy chair even more comfortable by treating it with a radiation-absorbing chemical.) While it might be some time before homeowners are comfortable enough with the idea to set up whole-body microwave heaters in houses, Buffler says microwaves may attract livestock farmers. Lambs that are born outdoors in winter, for example, are frequently lost to cold. Microwaves could warm the lambs safely and quickly. Which of the following statements about microwave heaters would Buffler most probably agree with? A) Microwave heaters will soon be widely used by homeowners. B) Microwave heaters sometimes make people feel uncomfortable. C) Perhaps microwave heaters will be first used by livestock farmers, who wish to protect their lambs in winter. D) Microwave heaters cannot be accepted by the public because they are somewhat unsafe.
C
English is the native or official language of one-fifth of the land area of the world. It is spoken in North America, Great Britain, Australia, and New Zealand. In South Africa and India it is one of the official languages. More people study English than any other language. In many countries, the textbooks in universities are in English. Many university classes are taught in English even though the native language is not English. English is the language of international communication. It is the language of international business, research, and science. More than three-fourths of the world's mail is written in English. More than half of the scientific research journals are in English. Most other languages have borrowed many English words. Why did English become the international language? In the middle of the nineteenth century, French was the international language. The Britain became very powerful in the world. England started colonies in North America and India in the seventeenth century. By 1900 England also had colonies in other parts of Asia, Africa and the South Pacific. The people in the colonies had to use English. Slowly it became more important than French internationally. After the Second World War, the United States became very powerful, and even more people began to learn English. Is English a good international language? It has more words than any other language. The grammar is simpler than in other major languages. However, English spelling is difficult. Foreigners all have trouble spelling English. So do native speakers! Since 1880, people have invented over fifty artificial (not natural) languages. No one speaks them as a native language. However, none of them has ever become popular. Some people don't want to study English, but it is the international language. There is no way to change that now. English is the native language of _ . A) South Africa B) Australia C) All of Canada D) Malaysia
B
Q: It can be hard to encourage families of preschoolers to turn off the TV,but there are plenty of highquality shows that promote learning and positive relationships rather than violence,researchers noted. "Although clearly kids watch too much,what's more worrying is that they watch poor quality shows," said Dr Christakis,the lead researcher on the new study from the University of Washington in Seattle.His former survey of parents of threeto fiveyearold children showed the kids often watched violent cartoons and movies that are "totally inappropriate". For their study,he and his colleagues randomly divide 565 preschoolers into two groups.In one group,parents recorded notes about kids' normal TV viewing,without receiving any guidelines to reduce or change those habits.In the other group,researchers made visits and calls and sent monthly newsletters encouraging parents to replace violent TV with educational programming.After six and 12 months,parents reported their kid's angry,aggressive or anxious behaviors on a questionnaire.At both time points,children in the TV intervention program had slightly fewer problems than those in the comparison group.Boys in lowincome families seemed to benefit most from the change in programming,the researchers found. "The point is,this is something that is as effective as other things we do to try to guide behavior in children,and it's fairly simple," Christakis said. Another study published in Pediatrics found the more TV kids and teens watched,the more likely they were to have a crime or other problems in society.Children may imitate violence they see--or more time in front of the TV could simply mean less communication with peers and families,and worse performance in school. The American Academy of Pediatrics recommends kids watch no more than one to two hours of highquality programming each day.Researchers agreed parents should be mindful of what exactly their young kids are watching on TV as well."It's not just about turning the TV off,it's about changing the channel,"... What is the positive effect of highquality TV shows on kids? A) Good learning results and relationships. B) Being affected by violence. C) Spending less time on TV programming. D) Encouraging them to turn on the TV.
A: A
(Q).
Research shows that humans switch from selfish to unselfish behavior when they are watched. Do you? A picture of a set of eyes on a computer screen can cause a change in the way people act. Even images of eyes on a charity donation, collection box encourage people to be unselfish, because people put more money in a collection box that has a picture of eyes on it than they do when a flower symbol is on the box. Manfred Milinski from the Max-Planck Institute for Evolutionary Biology in Germany and Bettina Rockenbach of the University of Berlin, the authors of a new study, found that people act better when they are being watched because they feel they will be rewarded for good behavior. Their report also referred to other research showing that this response of behaving well when watched is somehow _ into humans and people respond this way unconsciously, or without realizing it. It is not just humans that act unselfishly when they are being watched. A fish called the grooming fish cleans other fish. When other fish are around, it is gentler. When no other fish are around, however, the grooming fish bites chunks from the fish it is supposed to be cleaning. The researchers suggest that the best way to get people to behave in the correct way is to make them feel watched. This could be the reason for the success of a famous American army poster. On it was a picture of an elderly man staring fiercely and pointing, it appeared, to the person who was looking at the poster. Under the picture was the caption 'I Want You' It encouraged hundreds of thousands of young American men to join the army during the Second World War to fight the Germans and Japanese. Where would the study described in the text most likely be found? A) In a newspaper. B) In a scientific journal. C) In an advertising magazine. D) In a science textbook.
(A).
B