Question

【题目】根据短文理解，选择正确答案。
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 a long 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

【答案】
（1）B
（2）B
（3）D
（4）C
【解析】本文是说明文。文章介绍了科学家破解了海豚发出的一种哨声，这种哨声其实就是海豚的名字。

⑴细节理解。根据第一段的“Dolphins 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，海豚生活在黑压压的水下，什么也看不到，这决定了它们得用声音进行交流。所以答案是B。

⑵推理判断。根据第三段的“dolphins exchange whistles even when they're a third of a mile apart”和“That means dolphins shout out to group members that might be nearly five football fields away.”可知，这种哨音可以传播很远。所以答案是B。

⑶推理判断。根据第二段的“Scientists haven't uncovered their secret communication, except for one kind of whistle.”可知，本文是要向读者介绍海豚发出的一种奇特的声音的含义。所以答案是D。

⑷推理判断。根据第四段的句子“a baby dolphin plays with sounds throughout its first year. While testing its sound skills, a baby dolphin is doing something amazing.”可知，小海豚的名字是根据它自己发出的哨音确定的。所以答案是C。