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5. How did the accident come about? The driver refused to answer the policeman's question.

5. The driver refused to answer the policeman's question how the accident came about.

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 Talking plants might sound like characters in a fairy tale. But recent scientific studies have shown that plants communicate with each other and with other living things in a surprising number of ways. To understand them,scientists say,we just have to learn their language. Farmers are especially interested in what plants have to say.

  "Plants are able to communicate with all sorts of organisms (有机体) .They can communicate with giant bacteria,with other plants and with insects. They do this chemically," said Cahill,an Ecology Professor of the University of Alberta in Canada.

Plant scientists are just beginning to understand this chemical "language". Ca?hill says studies have shown,for example,that plants can evaluate (评估) condi?tions in their immediate environment and take appropriate action. Plants have an ability,for example,to signal pain or discomfort caused by anything from tempera?ture extremes to an insect attack. Jack Schultz,a professor of chemical ecology at the University of Missouri,says when a plant senses that it's being eaten,it cannot walk away from trouble; on the contrary,it will release a chemical vapour (蒸气) that alerts other plants nearby.

  "Their language is a chemical language,and it involves chemicals that move through the air that are easy to be changeable,and most of all are smells that we are familiar with," Schultz explained.

  "All plants responded to the attack by changing their chemistry to defend themselves," Schultz recalled. "But we were quite surprised to find that nearby plants also changed their chemistry to defend themselves* even though they were not part of the experiment."

  Studies have also shown that plants under attack release pleasant chemicals. Those chemicals attract friendly insects that attack the pests eating the plant.

In the end,plants' ability to communicate their needs―and our ability to un?derstand them―could help farmers reduce the use of poisonous chemicals,cut op?erating costs and limit damage to the environment.

5. The recent scientific studies have shown that plants can       .

   A. communicate with other living things in a chemical way

   B. hardly react to any sudden change in temperature

   C. use a very special chemical language which is familiar to us

   D. respond to the attack by giving off poisonous chemicals

6. When being eaten by a pest,the plant will       .

   A. walk away from trouble

   B. change its chemistry to kill the insect

   C. release a chemical vapour to "ask" other plants for help

   D. give off nice chemicals to attract friendly insects killing the pest

7. The underlined word "alerts" most probably means "       ”.

 A. warns   B. protects   C. threatens   D. allows

8. Which would be the best title for the passage?

   A. Communication between plants

   B. A chemical "language"

   C. Plants can talk

   D. How plants protect themselves

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