Water is very important to living things. Without water there can be no life on the earth. All animals and plants need water. Man also needs water. We need water to drink, to cook our food and to clean ourselves. Water is needed in offices, factories and schools. Water is needed everywhere.
There is water in seas, rivers and lakes. Water is found almost everywhere. Even in the desert part of the world, there is some water in the air. You can not see or feel it when it is a part of the air. The water in the seas, rivers and lakes is a liquid, the water in the air is a gas, and we call it water vapour (蒸气).
Clouds are made of water. They may be made of very small drops of water. They may also be made of snow crystals(结晶体). Snow crystals are very very small crystals of ice. Ice is frozen water. It is a solid. There can be snow and ice everywhere in winter.
Water may be a solid or a liquid or a gas. When it is a solid, it may be as hard as a stone. When it is a liquid, you can drink it. When it is a gas, you can not see or feel it.
【小题1】Where can we find water?

A．We can find water when it turns into vapour.

B．Water is only in seas and rivers.

C．We can see water in deserts here and there.

D．Water can be found almost everywhere.

【小题2】 We can drink water when it is       

A．a solid	B．aliquid
C．in the air	D．turned into ice

【小题3】Clouds are made of           

A．seas, rivers and lakes

B．blocks of ice

C．very small drops of water or snow crystals

D．solid, liquid and gas

【小题4】Water has three states(状态). They are              

A．solid, liquid and gas

B．solid, vapour, snow

C．drops of water, blocks of ice and crystals of water

D．ice, snow and air

Weather changes when the temperature and the amount of water in the atmosphere change. We can see and feel water coming from the atmosphere when we have rain. But the water must somehow get back to the atmosphere. Meteorologists call this the water cycle.

   There are many stages in the water cycle. Rain falls when water vapour in clouds condenses(凝结). Drops of water form and fall to the ground. The water soaks into the ground and feeds streams and rivers. A lot of rain falls into the sea. The heat of the sun evaporates some of the water in the ground and in the rivers, lakes, and the sea. It changes the liquid water into water vapour. The vapour rises onto the air. Water vapour is normally invisible. On a very damp or humid day, however, you can sometimes see water vapour rising from a puddle(水坑) or pond in a mist(薄雾) above the water. Water vapour also gets into the air from living things. Trees and other plants take in water through their roots and give off water vapour from their leaves. People and land animals drink water and breathe out water vapour. In all these ways the water returns to the air. There it gathers to form clouds and condenses to form rain. The rain falls to earth, and the cycle starts again. It continues even if snow or hail(冰雹) fall instead because both eventually melt to form water. The amount of water vapour in the air depends on the temperature. The air is more moist(潮湿) in the tropics(热带) than in the cold polar regions.

What is the main idea of the passage?

A. Water cycle.    B. Water vapour. C. How rain forms.   D.Water, vapour, rain.

How many ways of the water returning to the air are discussed in the text?

A. Two.   B. Three.   C. Four.     D. Five.

Whether water vapour can be seen or not depends on _______.

A. how much water is evaporated         B. how good your eyes are

C. in which way water is evaporated           D. climate or weather

From the passage we get to know _______.

A. there is more water vapour in the air in the tropics than in cold polar regions

B. there is more water vapour in the air in cold polar region than in the tropics

C. it gets more rain in the tropics than in cold polar regions because there is less vapour

D. the amount of water vapour in the air depends on how often it rains

It was once thought that air pollution affected only the area immediately around large cities with factories and/or heavy automobile traffic. Today, we know that although these are the areas with the worst air pollution, the problem is literally worldwide. On several occasions over the past decade, a heavy cloud of air pollution has covered the entire eastern half of the United States and led to health warnings even in rural areas away from any major concentration of manufacturing and automobile traffic. In fact, the very climate of the entire earth may be affected by air pollution. Some scientists feel that the increasing concentration of carbon dioxide in the air resulting from the burning of fossil fuels(coal and oil) creating a greenhouse effect-holding in heat reflected from the earth and raising the world’s average temperature. If this view is correct and the world’s temperature is raised only a few degrees, much of the polar ice cap will melt and cities such as New York, Boston, Miami, and New Orleans will be under water.
Another view, less widely held, is that increasing particulate matter in the atmosphere is blocking sunlight and lowering the earth’s temperature-a result that would be equally disastrous（灾难的）. A drop of just a few degrees could create something close to a new ice age, and would make agriculture difficult or impossible in many of our top farming areas. At present we do riot know for sure that either of these conditions will happen(though one recent government report prepared by experts in the field concluded that the greenhouse effect is very likely). Perhaps, if we very lucky, the two tendencies will offset each other and the world’s temperature will stay about the same as it is now.
【小题1】As pointed out at the beginning of the passage, people used to think that air pollution ______.

A．caused widespread damage in the countryside

B．affected the entire eastern half of the United States

C．almost brought worldwide effect

D．existed merely in urban and industrial areas

【小题2】As far as the greenhouse effect is concerned, the author _____________.

A．shares the same view with the scientists

B．is uncertain of its occurrence

C．rejects it as being ungrounded（无根据的）

D．thinks that it will increasingly destroy the world soon

【小题3】It can be inferred from the passage that                   .

A．raising the world’s temperature a little would not do much harm to life on the earth

B．lowering the world’s temperature a little would lead to agricultural disasters

C．almost no temperature variations have occurred over the past decade

D．the world’s temperature will remain stable forever

【小题4】This passage is primarily concerned with             .

A．the greenhouse effect in the world

B．the measures to adjust the climate

C．the potential effect of air pollution

D．the measures to protect the environment

When did you see a polar bear ? On a trip to a zoo, perhaps ? If you had attended a winter activity in New York a few years ago, you would have seen a whole polar bear club. These  “Polar Bears” are people who meet frequently in the winter to swim in freezing cold water. That day, the air temperature was 3 degrees. And the water temperature was a little higher. The members of the Polar Bear Club at Coney Island, New York are usually about the age of 60. Members must satisfy two requirements. First, they must get along well with everyone else in the group; this is very important because there are so many different kinds of people in the club. Polar Bears must also agree to swim outdoors at least twice a month from November through February.

Doctors don’t agree about the medical effects of cold-water swimming. Some are worried about the dangers of a condition in which the body’s temperature drops so slow that finally the heart stops. Other doctors, however, point out that there is more danger of a heart attack during summer swimming because the difference between the air temperature and the water tempreature is much greater in summer than in winter.

The Polar Bears themselves are satisfied with the benefits of cold-water swimming. They say that their favorite form of exercise is very good for the circulatory system (循环系统) because it forces the blood to move fast to keep the body warm. Cold-water swimmers usually turn bright red after a few minutes in the water. A person who turns blue probably has a very poor circulatory system and could not try cold-water swimming.

The main benefits of cold-water swimming are probably mental. The Polar Bears love to swim all the year round; they find it fun and relaxing. As one 70-year-old woman says, “When I go into the water, I pour my troubles into the ocean and let them float away.”

1.Doctors _________ .

A. have different ideas about the medical effects of cold-water swimming

B. believe swimming is helpful both in summer and in winter

C. enourage people to take part in cold-water swimming

D. point out the possible danger of blood illness during cold-water swimming

2.According to the passage, some doctors believe it is true that _______ .

A. Polar bears are bears swimming in freezing water    

B. cold-water swimming can make the body temperature dangerously high

C. you are healthy if cold-water swimming turns your skin color blue

D. cold-water swimming causes more heart attack in summer than in winter

3.The Polar Bears like to swim year-round, for _______ .

A. it is an easy way to keep the body warm in winter

B. they can stay young

C. they find it enjoyable and interesting

D. they might meet fewer troubles in life

4.Which of the following is TRUE according to the text ?

A.The Polar Bear is a club in which people swim to protect polar bears.

B. The club members are all over 60 years old.

C. There is no woman in the club.

D. None of the above.

5.This passage is mainly about _______ .

A. the requirements of the Polar Bear Club

B. a group of cold-water-swimming lovers

C. the Polar Bears’ life in New York

D. doctors’ ideas about cold-water swimming

 

Water is very important to living things. Without water there can be no life on the earth. All animals and plants need water. Man also needs water. We need water to drink, to cook our food and to clean ourselves. Water is needed in offices, factories and schools. Water is needed everywhere.
There is water in seas, rivers and lakes. Water is found almost everywhere. Even in the desert part of the world, there is some water in the air. You can not see or feel it when it is a part of the air. The water in the seas, rivers and lakes is a liquid, the water in the air is a gas, and we call it water vapour (蒸气).
Clouds are made of water. They may be made of very small drops of water. They may also be made of snow crystals(结晶体). Snow crystals are very very small crystals of ice. Ice is frozen water. It is a solid. There can be snow and ice everywhere in winter.
Water may be a solid or a liquid or a gas. When it is a solid, it may be as hard as a stone. When it is a liquid, you can drink it. When it is a gas, you can not see or feel it.
【小题1】Where can we find water?

A．Water can be found almost everywhere

B．We can find water when it turns into vapour.

C．Water is only in seas and rivers.

D．We can see water in deserts here and there.

【小题2】We can drink water when it is     .

A．a solid

B．in the air

C．aliquid

D．turned into ice

【小题3】Clouds are made of     .

A．seas, rivers and lakes	B．solid, liquid and gas
C．very small drops of water or snow crystals	D．blocks of ice

【小题4】Water has three states(状态). They are        .

A．solid, liquid and gas

B．solid, vapour, snow

C．drops of water, blocks of ice and crystals of water

D．ice,snow and air