We sleep every day. Anybody knows that we humans need ____1____. But even the scientists can't explain（解释）____2____ people sleep. All mammals（哺乳动物）, birds and other animals ____3____ need sleep. Some sleep on a tree, ____4____ some（such as dolphins 〈海豚〉）sleep while ____5____ Have you ever noticed the fish when they are sleeping? Yes, they are sleeping ____6____ open eyes.

　　Some scientists think that sleep may help ____7____ animals by taking them out of danger. Some scientists say that smaller animals sleep longer than larger ____8____, for example, a horse sleeps for 3 hours a day. But why do animals sleep? The ____9____, scientists say, may be something obvious（显而易见的）or ____10____ not yet dreamed of（出乎意料的）.We just don't know it.

阅读短文，把题后A～E五个句子还原到文中空缺处，使短文内容完整正确。

Can dolphins talk? Maybe they can't talk with words，but they can talk with sounds．  1 They are mammals （哺乳动物）, but they swim together in a group．

Dolphins talk to the other dolphins in a group．They give information．They say "Welcome" when a dolphin comes back to the group．  2   They talk when they play．

They make a few sounds above water．  3  People can not hear these sounds because they arc very．very high．Scientists make tapes of the sounds and study them．

Sometimes people catch a dolphin for a large aquarium．（An aquarium is a zoo for fish．） People can watch the dolphins in a show．Dolphins don't like to he away from their group in an aquarium．  4  

There are many stories about dolphins．They help people．  5   Dolphin meat is good，but people don’t like to kill them．They say that dolphins can bring good luck to them．Many people believe this．

Can dolphins talk? Maybe they can’t talk with words, but they talk with sounds. They show their feelings with sounds.
Dolphins travel in a group. We call a group of fish a “school”. They don’t study, but they travel together.
Dolphins are mammals（哺乳动物）, not fish, but they swim together in a school. Dolphins talk to the other dolphins in the school. They give information. They tell when they are happy or sad or afraid. They say“welcome”when a dolphin comes back to the school. They talk when they play.
They make a few sounds above water. They make many more sounds under water. People can’t hear these sounds because they are very, very high. Scientists make tapes of the sounds and study them.
Sometimes people catch a dolphin for a large aquarium.(An aquarium is a zoo for fish.) People can watch the dolphins in a show. Dolphins don’t like to be away from their school in an aquarium. They are sad and lonely.
There are many stories about dolphins. They help people. Sometimes they save somebody’s life. Dolphin meat is good, but people don’t like to kill them. They say that dolphins bring good luck. Many people believe this.
【小题1】A school of dolphins means_____.

Can dolphins talk? Maybe they can’t talk with words, but they talk with sounds. They show their feelings with sounds.

Dolphins travel in a group. We call a group of fish a “school”. They don’t study, but they travel together.

Dolphins are mammals（哺乳动物）, not fish, but they swim together in a school. Dolphins talk to the other dolphins in the school. They give information. They tell when they are happy or sad or afraid. They say“welcome”when a dolphin comes back to the school. They talk when they play.

They make a few sounds above water. They make many more sounds under water. People can’t hear these sounds because they are very, very high. Scientists make tapes of the sounds and study them.

Sometimes people catch a dolphin for a large aquarium.(An aquarium is a zoo for fish.) People can watch the dolphins in a show. Dolphins don’t like to be away from their school in an aquarium. They are sad and lonely.

There are many stories about dolphins. They help people. Sometimes they save somebody’s life. Dolphin meat is good, but people don’t like to kill them. They say that dolphins bring good luck. Many people believe this.

1.A school of dolphins means_____.

A．a zoo for dolphins                       B．a show by dolphins

C．a group of dolphins                      D．a library of dolphins

2. A dolphin feels _____in an aquarium.

A．afraid

B．happy with people watching them

C．lucky

D．sad and lonely

3.Which sentence is true?

A．Dolphins talk with words.

B．Dolphins always bring good luck.

C．Dolphins make more sounds above water.

D．Dolphins can’t breathe（呼吸） under the water.

4.People can’t hear the dolphins’ sounds because they are         .

A．low              B．high              C．soft              D．quiet

5.From the passage we know_____.

A．Dolphins travel together.

B．Dolphins talk with words when they play.

C．Dolphins like to live in aquariums.

D．All people want to catch dolphins and eat them.

Dolphins are not fish．They are mammals（哺乳动物）．They live in groups and speak to each other in their own language．But they are quite different from almost all land animals．Their brain is as big as man's and they live a long life--at least 20-30 years．

Like some animals，dolphins use sounds to help them find their way around．They also use sounds to talk to each other and to help them find food．They do not use their ears to receive sounds，but use the jaw-the lower part of the mouth．

It is strange that dolphins are friendly to men，and for thousands of years，there are many stories about dolphins and men．In the 19th century，in a dangerous part of the sea near New Zealand，there was a dolphin．The seamen liked him very much and gave him a very good name，Jack．From 1871 to 1903，Jack met every boat in the area and showed it the way．In 1903 a passenger on a boat with the name of The Penguin shot and hurt Jack．Luckily the dolphin didn't die，and after a long time he was well again．He guided the ships through the area for nine more years，but he refused to help the boat The Penguin．

Today，some people still kill dolphins，but many countries in the world now protect them．In these places，people are not allowed to kill them．

1．The underlined word “jaw” means ________ in Chinese．

A．下颚                   B．嘴巴                    C．嘴唇                      D．鼻子

2．How do dolphins find their way?

A．They use their noses to smell the way．              B．They use their ears to hear the sounds．

C．They use their eyes to see the way．            D．They use sounds to find the way．

3．Who was Jack?

A．The writer．        B．A dolphin．          C．A seaman．            D．The passenger．

4．The dolphin guided the ships for about ________．

A．32 years              B．9 years                C．41 years                 D．23 years

5．According to the passage，which of the following is NOT right?

A．Dolphins are not fish．

B．Dolphins don't live in groups．

C．Dolphins are kind and friendly to people．

D．Dolphins can live a long time．

　　Dolphins travel in groups. We call a group of fish a“__2__”. They don't study, but they travel together. Dolphins are mammals（哺乳动物）, not fish, but they swim together in a school. Dolphins talk to the other dolphins in the school. They give information. They tell when they are happy or __3__ or afraid. They say“Welcome”when a dolphin comes back to the school. They make __4__ sounds under water. People can't hear these sounds because they are very, very high. Scientists make tapes of the sounds and __5__ them.