学进去

   Fish hear sounds, though they have simply no ears outside their bodies. However, fish do have ears inside their bodies near the brain, and they hear very well with them. Some fish have been taught to recognize the difference between sounds better than some human beings do.

Many underwater animals make noises only by chance while they are doing something else. Other sounds are real communications of a simple sort, telling one fish of the presence and direction of another. A few noises may be warning messages or discovery of food, etc. The earliest scientific report on fish sounds referred to one of these.

A new field in science is learning to recognize and use underwater　sounds. It relies on the same skill that man has shown in recognizing birds and other land creatures by their calls. But this method is a greater challenge than bird watching, for many of the animals of the sea cannot be followed in any other known way. Their voices cry for attention. Yet we still have too little knowledge about many of the call makers. Perhaps the meaning of the calls and what the call makers are will some day be made known more carefully. It is as though the great oceans were for daring man to invade (涌人) them and to learn the secrets of the place from which his forefathers came so long ago.

1．According to the passage,fish hear sounds well with___________.

A．ears outside their bodies	B．brains
C．bodies	D．ears inside their bodies

2．Which of the following is true of the noises made by underwater　　 animals?

A．None of them is meaningless.	B．They are all actual communication.
C．They cannot be heard by human beings.	D．some of them are meaningless.

3．Recognizing underwater animals by their sounds____________.

A．is totally different from recognizing land creatures by their calls

B．will change people's knowledge of fish

C．is more or less a battle

D．is more difficult than recognizing land creatures by their calls

4．The animals of the sea can make voices with different purposes EXCEPT__________

A．telling the direction of some animals	B．crying for attention
C．telling the presence of some animals	D．crying for scientific report

5．From the last sentence, we can learn that __________.

A．more secrets of the great oceans are to be found out

B．the human beings have invaded the oceans for long

C．only very brave people can make use of them

D．people are fighting each other to become the master of the great oceans