Global warming is when the earth heats up, the temperature rises. It happens when greenhouse gases ---carbon dioxide, water vapor, nitrous oxide(二氧化氮), and methane(沼气) trap heat and light from the sun in the earth’s atmosphere, which increases the temperature. This is like when heat is trapped in a car. On a very hot day, the car gets hotter when it is out in the parking lot. This is because the heat and light from the sun can get into the car, by going through the windows, but it can’t get back out. Once the light is inside the car, it is trapped and the heat builds up, just like it does in the earth’s atmosphere. This is what the greenhouse effect does to the earth. The heat and light can get through the atmosphere, but it can’t get out. As a result, the temperature rises.

   Sometimes the temperature can change in a way that helps us. The greenhouse effect makes the earth appropriate for people to live on. Without it, the earth would be freezing, or on the other hand it would be burning hot. We would not get the sun’s heat and light to make the night somewhat warm. During the day, especially during the summer, it would be burning because the sun would be up with no atmosphere to filter(过滤) it, so people, plants, and animals would be exposed to all the light and heat.

  Although the greenhouse effect makes the earth able to have people living on it, if there gets to be too many gases, the earth can get unusually warmer, and many plants, animals, and people will die. They would die because there would be less food(plants like corn, wheat, and other vegetables and fruits). This would happen because the plants would not be able to take in the heat. This would cause us to have less food to eat, but it would also limit the food that animals have. Gradually, people, plants, and animals would all die of hunger.

   People are doing many things to try stop global warming. One thing people are doing is carpooling. Carpooling is driving with someone to a place that you are both going to. This minimizes the amount of greenhouse gases put into the air by a car. Another thing that people are doing is being more careful about leaving things turned on like the television, computer, and the lights. A lot of people are taking time away from the television, and instead, they are spending more time outdoors. This helps our planet out a lot. Now, more people are even riding buses, walking to school, and riding their bikes to lower the amount of greenhouse gases in the air.

   Planting trees and recycling also help. If you recycle, less trash goes to the dump, and less trash gets burned. As a result, there are fewer greenhouse gases in our atmosphere. Although adults do many things to help stop global warming, kids can do just as much.

68. By the example given in paragraph 1, the author wants to _______.

A. say that there are greenhouse gases in every car

B. show his feeling in a car in hot summer

C. tell us cars are causes of greenhouse gases

D. explain how greenhouse gases work

69. What is the effect of atmosphere?

A. It only traps the heat of the sun.

B. It makes the earth neither too hot nor too cold.

C. It works the same way as greenhouse gases.

D. It prevents all the light from the sun shining on the earth.

70. What is the main idea of the third paragraph?

A. Although greenhouse effect is necessary, too much of it causes us to die.

B. Human beings are likely to disappear from the earth.

C. Crops can’t take the heat if there is greenhouse effect.

D. If there is greenhouse effect, all the plants will die.

71. What will the author most probably discuss in the paragraph that follows?

A. Why cars and buses pollute the air a lot.

B. What global warming is doing to the environment.

C. What kids can do to help stop global warming.

D. Who should be responsible for the environmental problems.

There was once a great war between two countries. The war had been going on for some time and the soldiers were starting to feel 　21 the long battle.

　　　 On a hot afternoon, a man was 　22 past a small group of soldiers digging a huge pit(坑). The group leader was shouting orders and threatening 23 if the work was not completed within the hour. The man riding the horse 　24 and asked，“Sir, why are you only shouting orders? Why cannot you help them yourself?”

　　　 The group leader looked at him and replied, “What do you 25 ? I’m the leader. The men do as I 26 them to.” He then added,“If you feel so strongly about helping them, you are 　27　 to do so yourself!”

　　　 The man got down from the　 28 and started walking up to the soldiers at work. The group leader was simply 　29 !The man took up the 　30 and started helping the soldiers and worked with them till the job was 　31 !

　　　 Before leaving, the man 32 the soldiers on their work, and 　33 the group leader. He said, “Next time your　 34　 prevents you from supporting your people, you should inform your 　35 authorities, and I will provide a more permanent 36 .”

　　　 The group leader was now completely surprised. Only now he looked 　37 at the man and realized the man was the army general!

　　　 The army general exhibited some of the key 　38 that are important for a true leader. There are 　39 people who are ready to really help get the work done. They　 　　40 the status of the leader but not the state of the leader.

21.　 A. astonished at B. tired of C. frightened of D. embarrassed at

22. A. walking　　　　　　　 B. riding　　　　 　 C. driving 　　　　　　　　　 D. running

23. A. illness　　　　　　　　　　　 B. battle　　　　　　　　 　 C. punishment　　　 D. death

24. A. stopped　　　　　　　 B. waited　　　 　 C. stayed　　　　　　　 D. doubted

25.　 A. remember　　　　 B. mean　　　　　　　　　　　 C. express　　　　　　　　　 D. imagine

26. A. remind　　　　　　　 B. tell　　　　　　　　　　　　　 C. beg　　　　　　　　　　　　 D. invite

27.　 A. sure　　　　　　　　　　　　 B. lucky　 　　　　 C. ready　　　　　　　　　　　 D. welcome

28.　 A. horse　　　　　　　　　　　 B. plane　　　　　　　　　　　 C. car　　　　　　　　　　　　 D. bike

29.　 A. shocked　　　　　　　　　 B. moved　　　　　　　 C. encouraged　　　 D. worried

30.　 A. tools　　　　　　　　　　　 B. guns　　　　　　　　　　　 C. clothes　　　　　　　　　　 D. bricks

31.　 A. improved　　　　　　　　 B. lost　　　　　　　　　　　　 C. finished　　　　　　　　　 D. allowed

32.　 A. thanked B. rewarded C. instructed D. congratulated

33.　 A. interviewed　　　 B. answered　　　　　　　　 C. tested　　　　　　　　　　　 D. approached

34.　 A. people　　　　　　　 B. order　　　　　　　　　　　 C. leader　　　　　　　 D. status

35.　 A. richer　　　　　　　 B. higher　　　　　　　 C. cleverer　　　　　　　　　 D. smaller

36. A. prize　　　　　　　　　　　　 B. solution　　　　　　　　　 C. salary　　　　　　　 D. experiment

37. A. frequently　　　　　 　 B. closely　　　　　　　 C. seriously　　　　　　　　 D. firmly

38. A. problems B. courses C. qualities D. speeds

39.　 A. few　　　　　　　　　　　　 B. some　　　　　　　　　　　 C. most　　　　　　　　　　　 D. many

40.　 A. achieve　　　　　　　　　 B. call　　　　　　　　　　　　 C. prepare　　　　　　　　　 D. collect

There was once a great war between two countries. The war had been going on for some time and the soldiers were starting to feel 　21 the long battle.

　　　 On a hot afternoon, a man was 　22 past a small group of soldiers digging a huge pit(坑). The group leader was shouting orders and threatening 23 if the work was not completed within the hour. The man riding the horse 　24 and asked，“Sir, why are you only shouting orders? Why cannot you help them yourself?”

　　　 The group leader looked at him and replied, “What do you 25 ? I’m the leader. The men do as I 26 them to.” He then added,“If you feel so strongly about helping them, you are 　27　 to do so yourself!”

　　　 The man got down from the　 28 and started walking up to the soldiers at work. The group leader was simply 　29 !The man took up the 　30 and started helping the soldiers and worked with them till the job was 　31 !

　　　 Before leaving, the man 32 the soldiers on their work, and 　33 the group leader. He said, “Next time your　 34　 prevents you from supporting your people, you should inform your 　35 authorities, and I will provide a more permanent 36 .”

　　　 The group leader was now completely surprised. Only now he looked 　37 at the man and realized the man was the army general!

　　　 The army general exhibited some of the key 　38 that are important for a true leader. There are 　39 people who are ready to really help get the work done. They　 　　40 the status of the leader but not the state of the leader.

21. A. astonished at　　　　　　 B. tired of　　　　　　 　 C. frightened of　　 　 D. embarrassed at

22. A. walking　　　　　　　 B. riding　　　　 　 C. driving 　　　　　　　　　 D. running

23. A. illness　　　　　　　　　　　 B. battle　　　　　　　　 　 C. punishment　　　 D. death

24. A. stopped　　　　　　　 B. waited　　　 　 C. stayed　　　　　　　 D. doubted

25. A. remember　　　　 B. mean　　　　　　　　　　　 C. express　　　　　　　　　 D. imagine

26. A. remind　　　　　　　 B. tell　　　　　　　　　　　　　 C. beg　　　　　　　　　　　　 D. invite

27. A. sure　　　　　　　　　　　　 B. lucky　 　　　　 C. ready　　　　　　　　　　　 D. welcome

28. A. horse　　　　　　　　　　　 B. plane　　　　　　　　　　　 C. car　　　　　　　　　　　　 D. bike

29. A. shocked　　　　　　　　　 B. moved　　　　　　　 C. encouraged　　　 D. worried

30. A. tools　　　　　　　　　　　 B. guns　　　　　　　　　　　 C. clothes　　　　　　　　　　 D. bricks

31. A. improved　　　　　　　　 B. lost　　　　　　　　　　　　 C. finished　　　　　　　　　 D. allowed

32. A. thanked B. rewarded　　　　　　　　 C. instructed D. congratulated

33. A. interviewed　　　 B. answered　　　　　　　　 C. tested　　　　　　　　　　　 D. approached

34. A. people　　　　　　　 B. order　　　　　　　　　　　 C. leader　　　　　　　 D. status

35. A. richer　　　　　　　 B. higher　　　　　　　 C. cleverer　　　　　　　　　 D. smaller

36. A. prize　　　　　　　　　　　　 B. solution　　　　　　　　　 C. salary　　　　　　　 D. experiment

37. A. frequently　　　　　 　 B. closely　　　　　　　 C. seriously　　　　　　　　 D. firmly

38. A. problems　　　　　　　　　 B. courses　　　　　　　　　 C. qualities　　　　　　　　　 D. speeds

39. A. few　　　　　　　　　　　　 B. some　　　　　　　　　　　 C. most　　　　　　　　　　　 D. many

40. A. achieve　　　　　　　　　 B. call　　　　　　　　　　　　 C. prepare　　　　　　　　　 D. collect

Global warming is when the earth heats up，the temperature rises.It happens when greenhouse gases—carbon dioxide，water vapor，nitrous oxide(二氧化氮)，and methane(沼气) trap heat and light from the sun in the earth’s atmosphere，which increases the temperature.This is like when heat is trapped in a car.On a very hot day，the car gets hotter when it is out in the parking lot.This is because the heat and light from the sun can get into the car，by going through the windows，but it can’t get back out.Once the light is inside the car，it is trapped and the heat builds up，just like it does in the earth’s atmosphere.This is what the greenhouse effect does to the earth.The heat and light can get through the atmosphere，but it can’t get out.As a result，the temperature rises.

Sometimes the temperature can change in a way that helps us.The greenhouse effect makes the earth appropriate for people to live on.Without it，the earth would be freezing，or on the other hand it would be burning hot.We would not get the sun’s heat and light to make the night somewhat warm.During the day，especially during the summer，it would be burning because the sun would be up with no atmosphere to filter(过滤) it，so people，plants，and animals would be exposed to all the light and heat.

Although the greenhouse effect makes the earth able to have people living on it，if there gets to be too many gases，the earth can get unusually warmer，and many plants，animals，and people will die.They would die because there would be less food (plants like corn，wheat，and other vegetables and fruits)．This would happen because the plants would not be able to take in the heat.This would cause us to have less food to eat，but it would also limit the food that animals have.Gradually，people，plants，and animals would all die of hunger.

People are doing many things to try to stop global warming.One thing people are doing is carpooling.Carpooling is driving with someone to a place that you are both going to.This minimizes the amount of greenhouse gases put into the air by a car.

Another thing that people are doing is being more careful about leaving things turned on like the television，computer，and the lights.A lot of people are taking time away from the television，and instead，they are spending more time outdoors.This helps our planet out a lot.Now，more people are even riding buses，walking to school，and riding their bikes to lower the amount of greenhouse gases in the air.

Planting trees and recycling also help.If you recycle，less trash goes to the dump，and less trash gets burned.As a result，there are fewer greenhouse gases in our atmosphere.Although adults do many things to help stop global warming，kids can do just as much.

1.By the example given in Paragraph 1，the author wants to ________.

A．explain how greenhouse gases work

B．show his feeling in a car in hot summer

C．tell us cars are causes of greenhouse gases

D．say that there are greenhouse gases in every car

2.The underlined word “it” in Paragraph 2 refers to “________”．

A．light? B．heat

C．temperature? D．greenhouse effect

3.What is the main idea of Paragraph 3?

A．If there is greenhouse effect，all the plants will die.

B．Human beings are likely to disappear from the earth.

C．Crops can’t take the heat if there is greenhouse effect.

D．Although greenhouse effect is necessary，too much of it causes us to die.

4.What will the author most probably discuss in the paragraph that follows?

A．Why cars and buses pollute the air a lot.

B．What kids can do to help stop global warming.

C．What global warming is doing to the environment.

D．Who should be responsible for the environmental problems.