A
Cats never fail to interest human beings. They can be friendly towards humans, but they lead a mysterious lives of their own as well. They never become tame(温顺) like dogs and horses. As a result, humans have learned to respect their independence.
Most cats remain doubtful of humans all their lives. One of the things that attracts us most about cats is the popular belief that they have nine lives. Obviously, there is good deal of truth in this idea. A cat’s ability to survive falls is based on fact.
Recently the New York Animal Medical Centre made a study of 132 cats over a period of five months. All these cats had one experience in common: they had fallen off high buildings, yet only eight of them died from shock or injuries. Of course, New York is the ideal place for such an interesting study, because there is no shortage of tall buildings. There are plenty of high-rise windowsills（窗台） to fall from! One cat, Sabrina, fell 32 storeys（层）, yet only suffered from a broken tooth. Cats behave like well-trained paratroopers (跳伞运动员), a doctor said. It seems that the further cats fall, the less they are likely to injure themselves. In a long drop, they reach speeds of 60 miles an hour and more. At high speeds, falling cats have time to relax. They stretch out their legs like flying squirrels. This increases their air-resistance and reduces the shock of impact (冲击力) when they hit the ground.
21. We find cats endlessly interesting because____________.
A. we feel there is a good deal we do not know about their lives
B. we believe that cats have nine lives
C. they are different from dogs and horses
D. they can reach a speed of 60 miles an hour while falling
22. Cats can survive great falls mainly because ____________.
A. the further they fall, the less likely they are to injure themselves
B. a cat’s ability to survive is based on fact
C. a falling cat relaxes its legs and so increases its air-resistance
D. they are unlikely to fall at a speed of more than 60 miles an hour
23. “Cats never fail to interest human beings” means ____________.
A. human beings are often interested in cats
B. cats seldom show any interest in human beings
C. cats are not interesting at all
D. human beings hardly show interest in cats
