Ants have the ability to smell out cancerous cells(癌细胞）in humans,which has been discovered by a new study,suggesting that they could be used to find cancer in the future. Researchers from the French National Center for Scientific Research (CNRS)discovered that some ants have a well developed sense of smell.“However more tests must be carried out before they could be used in hospitals."the team said.

　　The scientists did tests with 36 ants, smelling cells in the lab. First, they let the ants smell some cancerous human cells. Every time the ants smelt cancerous cells, they were rewarded with sugar solution(糖液).In the second step,the ants were put into two different smells. One was a new smell of healthy cells and the second was still the smell of the cancerous cells. Once the ants found the cancerous cells successfully,the researchers made them smell different cancerous cells. As such,the scientists found that ants could discriminate(辨别）between cancerous and healthy cells and between two cancerous cells.

　　This isn't the first time that scientists have used the animals' sense of smell to find cancerous cells.“Dogs are good at finding something with their noses. However, training dogs to do so requires several months to a year. On the other hand, insects can be easily raised, they are inexpensive, and hundreds of them can be trained with fewer times,"the researchers pointed out.

　　“This study shows that ants are able to learn very quickly. The method can be used for other tasks including finding danger or other diseases.”the researchers added.

　　1.What can we know from CNRS's study?

　　A. Ants work well in treating cancer.

　　B. Ants help humans keep off cancer.

　　C. Ants are able to smell out cancerous cells.

　　D. Ants are used to find people with cancer.

　　2.Which paragraph tells how the scientists did the tests?

　　A. Paragraph 1. B. Paragraph 2.

　　C. Paragraph 3. D. Paragraph 4.

　　3.In the tests，what did the scientists do if the ants worked well?

　　A. They set the ants free.

　　B. They gave the ants sugar solution.

　　C. They put the ants into different smells.

　　D. They separated the ants from other ants.

　　4. What are the advantages of insects compared with dogs in experiments?

　　①They are cheaper.

　　② They are easier to be raised.

　　③ They are better at finding things.

　　④ They can be trained more quickly.

　　⑤ They have a sharper sense of smell.

　　A. ①②③ B.①②④ C.①③④ D.②③⑤

　　5.Which section of a magazine is the text probably from?

　　A. Culture World.

　　B.Teenage Problems.

　　C.Sports and Games.

　　D. Biology and Science.

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