Dolphins（海豚）are not fish, but warm-blooded animals. They live in groups, and speak to each other in their own language. In this, they are like other animals, such as bees and birds. But dolphins are very different from almost all land animals. Their brain is nearly the same size as our own, and they live a long time―at least twenty or thirty years. Like some animals, dolphins use sound to help them find their way around. They also make these sounds to talk to each other and to help them find food. We now know they do not use their ears to receive these sounds, but the lower part of the mouth, called the jaw.
Strangely, dolphins seem to like man, and for thousands of years there have been stories about the dolphin and its friendship with people.
There is a story about sailors in the 19th century. In a dangerous part of the sea off the coast of New Zealand, they learnt to look for a dolphin called Jack. From 1871 to 1903, Jack met every boat in the area and showed it the way. Then in 1903 a passenger on a boat called The Penguin shot and wounded Jack. He recovered and for nine years more continued to guide all ships through the area－except for The Penguin.
Today, some people continue to kill dolphins, but many countries of the world now protect them and in these places it is against the law to kill them.
【小题1】Dolphins are different from many other animals in that they . A．live in groupsB．have large brainsC．are warm-bloodedD．have their own language【小题2】Which of the following does the dolphin use to help it find its way around? A．Its nose.B．Its ears.C．Its mouth.D．Its eyes.【小题3】Why did the sailors off the coast of New Zealand look for Jack? A．He was lonely and liked to be with people. B．They enjoyed playing with him. C．He was seriously wounded. D．They wanted his help.【小题4】By telling the story of Jack, the writer wanted to show that . A．dolphins are friendly and cleverB．people are cruel to animals C．Jack is different from other dolphins D．dolphins should be protected by lawB
网友回答
(答案→)B
解析：本文介绍了海豚的情况，并举例说明海豚是人类的朋友。
【小题1】细节题：由第一段第五句Their brain is nearly the same size as our own,可知海豚与其他动物最大的不同就是他们的脑子和人类的脑子几乎一样大，故选B。
【小题2】细节题。由第一段第六句dolphins use sound to help them find their way around.可知海豚是通过声音确定方向的，故选C。
【小题3】由第三段Jack met every boat in the area and showed it the way.可知海员们寻找Jack的原因是Jack为这些航船在危险航段指明方向，故选D。
【小题4】全文都在讲海豚的聪明与友好，所以正确答案是A；其他三个选项不能涵盖全文，只是文章的一个细节。