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发表于 2016-7-14 17:35:27
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SectionB
Directions:In the following article, some sentences have been removed. For questions41-45, choose the most suitable one from the list A~G to fit into each of the numbered blank. There are two extra choices, which do not fit in any of the gaps。(10points)
Researchers have found that drugs used to treat human seizures can delay aging in worms by as much as 50 percent. The roundworms used for the study are similar to humans in their molecular makeup, raising the
possibility that the drugs could also extend the life span of humans。
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“By finding a class of drugs that delays aging we have found a relationship between the function of the nervous system and aging that was not well understood, ” said Kerry Komfeld, a geneticist at the Washington
University School of Medicine in St. Louis, Missouri. The findings are detailed this week in the journal Science。
The discovery came out of the thesis work by one of Komfeld’s graduate students, Kimberley Evason. About four years ago, Evason began exposing groups of the roundworm Caenorhabditis elegans to commercially available drugs to see if the drugs would delay aging or promote longevity。
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Over eight months the scientists tested 20 drugs, all with negative results. Finally they tested the anticonvulsant drug ethosuzimide. Researchers found that the drug extended the life span of roundworms from 16. 7 days to 19. 6 days, a 17 percent increase。
43
The discovery that the drugs extend the life span of roundworms could have important implications fox human aging as well. There are strong similarities on the molecular level between the proteins and genes that
constitute the worm and those that make up other animals, including humans。
“Many basic processes are highly related, including neural function, insulin signaling, and probably important aspects of the aging process, ” Komfeld said. “There’s every reason to think that these animals an a good model for higher animals, such as people. ”
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Ethosuzimide, which was developed in the 1950s, is commonly used to treat epilepsy, though it is no known precisely how the drug controls convulsions. There is no anecdotal evidence that it has had an anti-aglng effect in people. The next step, Komfeld says, is to test if the drugs have an anti-aging effect on animal like flies and mice。
Very little is known about the aging process. From genetic analysis, researchers have found that an in sulin-like signaling system regulates aging and longevity. A good diet can delay aging and extend a person life span. But scientists know virtually nothing about the effect of drugs on aging. “It’s a big void, ” Konfeld said。
In addition to delaying age-related degenerative changes, the drugs also increased neuromuscular activty, suggesting a link between the neuromuscular system and the aging process。
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There may also be other targets not yet explored that affect aging and neuromuscular function. Said Kornfeld: “The process of aging remains mysterious. ”
A. But Komfeld said scientists will not know about the applicability of the drugs in humans until a similar study is done on humans. “What’s very encouraging is that these drugs were developed to treat humans, and they are well understood, because they’ve been used for a long time, ” he said。
B. Later the scientists discovered that two related anticonvulsant drugs also lengthened the lives of the worms-in the case of one drug, by almost 50 percent. “This was a big surprise to use, Komfeld said. ”“We didn’t think anticonvulsant drugs had any particular relationship to aging. That connection was completely unexpected. ”
C. Roundworms are a poor subject for experiments, because they are not like humans, even though their molecules are similar. For example, they have no bones, nor do they show emotions, making it difficult to know how exactly human subjects would react to these drugs in large quantities. However, using the worms allows experiments to be conducted quickly, because they do not live for long。
D. “Somehow the neural activity seems to regulate the aging of all of the body the skin, musculature, and reproductive tract, ” Kornfeld said. “Somehow the nervous system coordinates the progress of all these tissues, evidently, though the life stages. But we don’t know how it does that. ”
E. The discovery may also shed light on the little-understood aging process. Since the drugs act on the neuromuscular systems of both humans and worms, the findings hint at a link between neural activity and aging。
F. Unlike vertebrates, the worms are ideal subjects for the study of aging because of their short life spans, which last only a couple of weeks in a laboratory. The worm is well known in genetics, and the worm’s genome has been sequenced。
G. Use of this drug has been permitted by law since 1998 and wider use is now expected as a result of the studies. “We can clearly link this drug with human aging, but we still need to find proof, says Kornfeld optimistically. ” PartⅢ Translation
Directions: Translate the following passage into Chinese and put your translation on the ANSWER SHEET。(15points)
Last Sunday,China’s central bank governor Zhou Xiaochuan said if necessary,the nation will consider widening the yuan’s trading band。
But any change in the yuan’s floating band will depend on the global economic situation and it’s not the only tool the country would use to make its currency more flexible,Zhou said at the Group of 20 meeting in Cape Town,South Africa。
China widened the yuan’s daily trading band against the U.S. dollar from plus or minus 0. 3 percent to 0. 5 percent in May。
However,market observers said some commercial banks are ordered by the central bank to hand in reserve requirements in foreign currencies next week,which will translate into demand for the U.S. dollar. This will somehow help slow down RMB’S appreciation against the greenback in the coming few days。
PartⅣ Writing
Section A
Directions: Write a letter of application for the position an Director of a Computer-Aided Learning Center. Try to make the letter interesting and show that you have enthusiasm for the job. Also state the qualifications you have for the job and your work experience. (10points)
Section B
Directions:Study the following pie chart carefully and write an essay based on the tips:
(1) Describe the picture。
(2) Show your understanding of the symbolic meaning of the picture below。
(3) Give your opinions or advice。
You should write at least 150 words neatly on ANSWER SHEET. (15points)
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