It's warm and wet in the south of China, ________ it is cold and dry in the north.

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A. but 　　　　　　　　  B. while 　　　　　　   C. and 　　　　　　　　 D. so

 All in all, plants in warm and wet areas grow quicker than         in cold and dry areas, but the quality of the former is much worse than         of the latter.

A. these, those               B. that, this        C. those, that         D. the ones, one

How would you like to brush a crocodile’s teeth? Or give a shark a bath? Cats are well-known for the way they keep themselves clean by licking （舔）, but other animals have their own ways to stay clean as well. And tidiness can be important for their survival. Even cockroaches （蟑螂） have to keep their feelers clean to help them into food.

Many animals in the wild, such as deer, wolves and bears, have an automatic cleaning system. Insects like to attach themselves to animals to feed on the skin or blood. These parasites （寄生虫） can be unhealthy. But their “host” animals are constantly dropping skin and fur by a natural process. They also like to rub up against trees or rocks to comfort themselves, and this removes additional skin and fur. Along with old fur goes the dirt and parasites living in the fur. While these animals may sometimes take a bath when they enter or cross a river or lake, they don’t need the water to stay clean. They don’t get sweaty, because they don’t have sweat glands （汗腺） all over their bodies the way people do. Growing new skin and fur is enough to keep them clean.

Some animals and birds use dust to get clean. Chinchillas, a kind of small animal that lives in the mountains of South America, have a very fine fur. （They are raised for their fur, in fact.） If they took water baths, they might get too cold. So, instead, they roll around in fine dust, raising quite a cloud as they “bathe”. The dust helps to keep their fur and skin dry. This protects them from bacteria and parasites that enjoy warm and wet places. And the fine dust doesn’t stick in their fur for long. It falls off or blows away.

As for lions and tigers, their rough tongues act like combs and can remove dirt and loose fur. Why is it important for them to stay clean and smooth? It helps them stay cool in very hot summer or feel warm in cold winter.

64. What’s the main idea of this passage?

A. Animals enjoy living in a clean environment.

B. Animals fight against parasites in different ways.

C. Unlike people, animals hate staying in water.

D. For animals, cleanliness is a survival skill.

65. According to the passage, such animals as deer, wolves and bears clean themselves by        .

A. living with parasites

B. replacing their skin and fur naturally

C. climbing trees or rocks

D. having a bath in a river or lake

66. It can be inferred from the passage that the way some animals stay clean        .

A. is decided by their physical conditions

B. is better than the way people do

C. keeps them away from parasites all the time

D. helps them survive any danger in the wild

Millions of years ago dinosaurs (恐龙) lived on the earth. In the days of dinosaurs the whole earth was warm and wet. There were green forests and they could find enough to eat. Later, parts of the earth became cold and dry. and the forests there died. Then dinosaurs could not find enough to eat. This must be one reason why dinosaurs died out.

We can guess another reason. New kinds of animals came on the earth. Some had big brains and were fast and strong. They could kill dinosaurs. There may be other reasons that we don’t know about yet. Scientists are trying to make more discoveries about dinosaurs.

Dinosaurs were of many sizes and shapes (形状).  Some were as small as chickens, while some were about 90 feet long.

There were also terrible fights between dinosaurs. They might have happened more than 100 million years ago. Though there was no man to see any of the fights, we can be told by the animal’s footprints (足迹) that fight did take place.

1.According to the passage, dinosaurs did exist only ______on the earth.

2.One reason why dinosaurs died out is that______.

3.One more reason may be that ______.

4.We can see from this passage ______.