Question

Dolphins(海豚) live in a dark underwater world. It’s often impossible to see each other or anything else around them, so sound plays an important role in their survival. To communicate with each other, dolphins produce all kinds of sounds.

Only other dolphins understand what the sounds mean. Scientists haven’t uncovered their secret communication, except for one kind of whistle. It might last less than a second, but this whistle is a big deal. Why? Because these whistles are actually names of dolphins - and every dolphin has one. Scientists call these sounds a “signature whistle.” When other dolphins hear the whistle, they know which dolphin is calling.

Dolphins often hunt by themselves but still need to stay connected to the group. Since they can’t always see each other, dolphins use their signature whistles to check in with other dolphins hundreds of yards away. “In coastal areas, dolphins exchange whistles even when they’re a third of a mile apart,” says Greg Campbell, who studies animals. That means dolphins shout out to group members that might be nearly five football fields away.

What’s amazing is who names the baby dolphin. Not the mother. Not an auntie dolphin or another group member. Scientists believe the baby dolphin itself comes up with the signature whistle. Like human babies, a baby dolphin plays with sounds throughout its first year. While testing its sound skills, a baby dolphin is doing something amazing. It’s creating or figuring out its signature whistle. How or why it chooses its signature whistle is not clear. Studies show that most of the time the signature whistle is nothing like its mother’s or group members’ whistles.

When the baby dolphin is about a year old, its signature whistle is set. It repeats it often so the other dolphins learn to recognize it.

Deciphering(破译) dolphin names is just the beginning of figuring out what dolphins communicate about. Do they chat about sharks? Discuss the tides? Maybe they even have a name for people. Someday scientists are to decipher the rest of dolphins’ communication.

1.Sound is important for dolphins because of ______.

A．their poor sense of direction

B．their living environment

C．their strong enemies

D．their big groups

2.The dolphin’s signature whistle ______.

A．lasts along time

B．can travel long distances

C．is especially helpful in hunting

D．can be recognized by other animals

3.The author writes the text mainly to _____.

A．encourage readers to study dolphins

B．tell readers how dolphins communicate

C．show how lovely and clever dolphins are

D．introduce a special sound made by dolphins

4.A baby dolphin gets its name ______.

A．soon after it was born       B．according to its size

C．all by itself                D．with the help of its group

Answer

1.B

2.B

3.D

4.C

【解析】

试题分析：本文告诉我们海豚主要是通过声音进行交流，在海豚交流的声音中有一种声音很特别：signature whistle。然后分别接着这种声音的特点。

1.B 推理题。根据文章第一段1、2句Dolphins(海豚) live in a dark underwater world. It’s often impossible to see each other or anything else around them, so sound plays an important role in their survival.可知海豚生活在深海中，周围一片漆黑，所以它们要使用声音交流。所以声音很重要是因为海豚的生存环境。故B正确。

2.B 细节题。根据文章第三段3、4句In coastal areas, dolphins exchange whistles even when they’re a third of a mile apart,” says Greg Campbell, who studies animals. That means dolphins shout out to group members that might be nearly five football fields away.可知海豚可以在很远的距离传递自己的signature whistle。故B正确。

3.D 主旨大意题。本文主要叙述的是由海豚发出的一种很特别的标志自己身份的signature whistle，先由海豚所发出的声音导入。然后具体介绍这种标志海豚身份的signature whistle的用途和特点。故D正确。

4.C 细节题。根据第四段第四句Scientists believe the baby dolphin itself comes up with the signature whistle.可知signature whistle是由小海豚自己想出来的。故C正确。

考点：考查科普类阅读