题目内容

Water never stops moving. Snow and rain fall to the earth from the sky. That water runs down into rivers and lakes, and sometimes it makes waterfalls. Finally, the water runs out into the sea.

How does water get up into the sky.'? It evaporates (蒸发) from the ground. The sun changes water into gas, and it goes up to make clouds. There, the cycle (循环) begins again.

     The cycle tells us that water may evaporate and change into clouds, but it’s still water. The water you drink could be the same water that dinosaurs drank!

     But too much of our water today has been polluted. Our water may never go away, but a lot of it is becoming too dirty for us to drink!

    1. Which of the following can be filled in the boxes below to show how water cycles?

A. (1) clouds, (2) rain, (3) rivers, (4) sea

B. (1) rivers, (2) clouds, (3) rain, (4) sea

C. (1) clouds, (2) rivers, (3) sea, (4) rain

D. (1) rivers, (2) sea, (3) rain, (4) clouds

2. Water evaporates because________

     A. it never changes

     B. it never stops moving

C. the sun turns it into gas

D. it runs into the sea

3. The underlined sentence means that________

A. water may change into other forms, but it’s still water

B. water may go away

C. there are still dinosaurs on the earth today

D. dinosaurs drink water as we do

4. The water problem we are facing now is that

A. too much of it has evaporated

B. a lot of water flows into the sea

C. a lot of water has been polluted

D. water can′t be recycled

5. The best tide for this passage is

A. Water pollution

B. How water changes into clouds

C. Evaporation

D. Water cycle

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We have always been warned of the dangers of forest fires. They cause _____ 85 _____ to a forest. They kill many plants and animals in an eco-system, which is a group of living things and their environment. But have you ever heard of a forest fire that can be _____86_____  for a forest? People start some of the fires with a special reason to actually do good to the eco-system.

In fact, fires are a natural part of any eco-system. Without fires, the oldest and largest trees would stop sunlight from reaching the forest floor. Fires can _____87_____ some of these old trees. When the trees die, they provide something good for the earth. New trees can grow strong and healthy in their place.

Some trees even need fires to grow. These trees hold their seeds (种子) inside. Heat from a fire allows the coat of the seeds to open up. Then the seeds fall to the ground and have the _____88____ to grow/

Scientist, who know about nature’s needs, start some of these fires, called controlled burns. A fire is started and kept under control. This way, the fire does not spread out of the area or _____89_____ a after forest fires, they can go hungry _____90_____ their food has been damaged in the fire. Small, controlled fires mean than animals will not have to move far to find food. After some time, small plants begin to grow. Animals return soon after the plants return. This _____91_____  makes an eco-system.

So the next time you hear about a forest fire, think about the good as well as the bad. It may take a new eco-system a while to return, but it will likely come back stronger and healthier than ever.

85. A) illness     B) difficulty      C) damage       D) flood

86. A) helpful    B) powerful      C) harmful       D) awful

87. A) take the place of    B)  get ready for     C)  be bad for      D) get rid of

88. A) time       B) water       C) chance       D) skill

89. A) discover    B) cover       C) but          D) waste

90. A) because    B) although      C) but         D) so

91. A) almost     B) again        C) never      D) even

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