Ladies and gentlemen,I return to this year in a time machine .In the year 2500,we are able to travel through time to any

Ladies and gentlemen,I return to this year in a time machine .In the year 2500,we are able to travel through time to any year in the history of the earth. This year is your last chance to change your lifestyle to save the earth.
Beginning in the middle of 20th century ,a few people were worried about polluting the earth’s water and air ,but most people did not change their ways of life .Instead, they continued to pour dangerous chemicals and other wastes into lakes and seas, to drive more and more cars and trucks, and to cut down trees.
By the year of 2200,the earth’s water was completely polluted. People could no longer drink water, and they had to use other types of liquids. Scientist said that in the future there will be too many people on the earthBut not enough was done
So ,by the year of 2300,there were so many people that food became scare .There was no water to grow food and all of the fishes in the lakes and seas died because of pollution. Terrible wars（战争） broke out between the rich and the poor. Scientists were working very hard to find another planet in space where humans could live.
By the year 2400,the air was too polluted for humans to breathe. So we had to leave the earth. But only the rich were able to leave. Where did we go? No –where. You see scientists did not find another safe planet, so now we must travel around the universe in our spaceships .We were still looking for a place to call our home.
So it is up to you to change history. There is sill hope. You must change your lifestyle now, before it is too late.
()36.Which problem is not talked about in paragraph 2(第二段)?
A. waterB. air C. lifestyleD. food
() 37. What’s the meaning of “scarce” in the passage?
A.昂贵的B.充足的 C.缺乏的 D.特殊的
（）38.Who could leave the earth by the year of 2400?
A. The rich B. The poor C. Scientists D. All the people
() 39.Which of the following is true?
A. Only a few people changed their lifestyles in the 20th century
B. There wasn’t enough water for people to drink by the year of 2200
C. All the animals died because of pollution by the year of 2300
D. We found a new home in another planet by the year of 2400()
40.What’s the titleof the passage?
A. Stop pollutingB. Change or leave C. Look for a new home D. Return to theearth