A
Dolphins (海豚) are not fish but mammals (哺乳动物)．They live in groups, and speak to each other in their own language. In this way they are like many other animals, like bees. But dolphins are very different from almost all land animals. Their brain (脑) is nearly the same size as humans', so they are the cleverest animals. And they live for 20 to 30 years.
But what does the dolphin look like？The dolphin has teeth, and eats fish. It can grow up to three and a half metres long. Its nose is very long. Like some other animals, the dolphin uses sound to find its way. They make sound to talk to each other and to help find food. We now know they don't use their ears to listen to the sound, but the jaws (颚)．
Dolphins are friendly to people. They often save people in the sea. So many people like them.
Not only adults but also teenagers have problems in their life. Here is a survey showing the main problems of teenagers.
They feel stressed because they have too much homework to do both at school and at home. They have lots of exams to take. And parents usually send them to different classes at weekends. They don't have their own time to do what they are interested in.
Now more and more teenagers are getting shortsighted. They often read in bed or keep reading for a long time without having a rest. Some of them are crazy about playing computer games. Some spend too much time watching TV.
Another serious problem among teenagers is that many of them are becoming fat. They eat too much junk food, but they take little exercise.
I think teenagers should think of ways to deal with problems. They should make a plan for study and hobbies and find time to relax as much as possible.
阅读短文，并按要求完成下列句子。
C
We know that many animals do not stay in one place. Birds, fish and other animals move from one place to another place at a certain time. They move for different reasons: most of them move to find food more easily, but others move to get away from places that are too crowded.
When cold weather comes, many birds move to warmer places to find food. Some fishes give birth in warm water and move to cold water to feed. The most famous migration is probably the migration of the fish which is called “salmon” (鲑鱼). This fish is born in fresh water but it travels many miles to salt water. There it spends its life. When it is old, it returns to its birthplace in fresh water. Then it gives birth and dies. In northern Europe, there is a kind of mouse. They leave their mountain homes when they become too crowded. They move down to the low land. Sometimes they move all the way to the seaside, and many of them are killed when they fall into the sea.
Recently, scientists have studied the migration of a kind of lobster (龙虾). Every year, when the season of the bad weather arrives, the lobsters get into a long line and start to walk across the floor of the ocean. Nobody knows why they do this, and nobody knows where they go. So, sometimes we know why humans and animals move from one place to another place, but at other times we don't. Maybe living things just like to travel.
①This kind of plant is very (稀少的)．It's difficult to find it.
②Scientists are doing (研究) on how to clean the polluted river.
③This (情况) often happens to people who travel by car.
④I don't think it's right to (杀) animals.
⑤Lucy was (发狂的) when she heard Michael Jackson's death.
⑥People need to help the animals live in (安宁，和平)．
⑦Tell me the (原因) why you were late.
⑧If I have (足够的) money, I'll buy a big house.
⑨Our (政府) is working hard to save pandas.
⑩All of us should love our beautiful (大自然)．
a. Yes, there are many.
b. Yes, they are.
c. I really enjoyed myself.
d. Does it eat meat?
e. I am riding the elephant.
Peter: Hi, Sally. Come and have a look at my photos.
Sally: Are these the photos you took in Africa, Peter?
Peter: Look, this is a wildebeest. It's an animal in Africa.
Sally:
Peter: No, it doesn't. It only eats grass.
Sally: Are there a lot of animals in Africa?
Peter:
Sally: Oh, this photo looks interesting. What are you doing there?
Peter:
Sally: Did you have a good time there?
Peter: Of course.
