阅读下列短文，从所给的四个选项中，选出最佳答案。Aquestionoftenputtospecialistsonfishesis"Howlongdofisheslive?"Specialistsfinditdifficulttogiveanexactanswerthoughits

Question

阅读下列短文，从所给的四个选项中，选出最佳答案。

　　     A question often put to specialists on fishes is "How long do fishes live?" Specialists find it difficult to give an exact answer though it seems to be a very simple question. Actually this question is not so simple as it seems. There are thousands of different kinds of fishes and they are different from one another in size and life-span (寿命). Moreover (此外) it is not easy to find out just how long a fish lives in its natural state.

　　     We can find out how old a fish is by studying its size but we cannot say how much longer it would have lived if we had not caught it.

　　     We may feed fishes and record their life-span but we cannot be sure that this is the length of time they would have lived if they had　　 been left alone.

　　     We may make markings to show how fast the fishes grow so that we can calculate (计算) the age of the largest on record but unless this large fish dies of old age we are still not in a position to know　　 its natural life-span.

　　     Unlike human beings fishes do not stop growing when they reach maturity (成年). They continue to grow as long as they live although　　 the rate of growth slows down in grown-up fishes.　　 　　

(1) What specialists feel difficult to know is ________.

[　　]

A. the age of fishes　　　　

B. the size of fishes　　　　

C. the life-span of the fishes he feeds 　　

D. the life-span of fishes living freely 　　

(2) We may know a fish's age by studying __________.

[　　]

A. how heavy it is　　

B. how big it is　　　　

C. its rate of growth　　

D. the position it lives　　

(3) Which of the following is true?

[　　]

A. The heavier a fish is the older it is. 　　

B. If we let a fish alone we can hardly know its life-span. 　　

C. Old as a fish is it will keep growing fast before its death. 　　

D. When a man is old he will grow much more slowly than an old fish. 　　

(4) Which of the following is not true?

[　　]

A. If we feed a fish from its birth to its death we correctly record its life-span.

B. A fish's weight has nothing to do with its life-span.

C. Human beings stop growing when they have grown up.

D. Specialists can know how fast a fish grows but they do not know how long it will live.　　

(5) Which of the following do you think is the best title for this　　 passage?

[　　]

A. How Long Do Fishes Live? 　　

B. Easy or Difficult?　　　　

C. The Difference Between Human Beings and Fishes. 　　

D. Specialists and Fishes.

Answer 1

答案：D;C;B;A;A