In study after study, it appears that these chemical conversations help the neighbors. The damage is usually more serious on the first plant, but the neighbors, relatively speaking, stay safer because they heard the alarm and knew what to do.

　　Does this mean that plants talk to each other? Scientists don't know. Maybe the first plant just made a cry of pain or was sending a message to its own branches, and so, in effect, was talking to itself. Perhaps the neighbors just happened to "overhear" the cry. So information was exchanged, but it wasn't a true, intentional back and forth.

　　Charles Darwin, over 150 years ago, imagined a world far busier, noisier and more intimate(亲密的)than the world we can see and hear. Our senses are weak. There's a whole lot going on.

1.What does a plant do when it is under attack?

　A.It makes noises.

　B.It gets help from other plants.

　C.It stands quietly.

　D.It sends out certain chemicals.

2.What does the author mean by"the tables are turned"in paragraph 3?

　A.The attackers get attacked.

　B.The insects gather under the table.

　C.The plants get ready to fight back.

　D.The perfumes attract natural enemies.

3.Scientists find from their studies that plants can　　　.

　A.predict natural disasters

　B.protect themselves against insects

　C.talk to one another intentionally

　D.help their neighbors when necessary

4.What can we infer from the last paragraph?

　A.The world is changing faster than ever.

　B.People have stronger senses than before.

C.The world is more complex than it seems.