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? Nowhere. You see scientists did not find another safe planet，so now we must travel around the universe in our space ships. We are still looking for a place to call our home.
So it is up to you to change history. There is still hope. You must change your lifestyle now, before it is too late.
30 .Which problem is NOT talked about in Paragraph2?
A. Water. B. Air. C. Lifestyle. D. Food.
31. The underlined word "scarce" means " ".
A.昂贵的 B.充足的 C.缺乏的 D.特殊的
32. Which of the following is NOT true?
A. Only a few people changed their lifestyle in the 20th century.
B. There was no clean water for people to drink by the year 2200.
C. All the fish died because of the pollution by the year 2300.
D. We found a new home in another planet by the year 2400.
33. What's the best title of the passage?
A. Stop polluting B. Change or leave
C. Look for new home D. Return to the earth
C
"Listen carefully to what I say, " the time traveller said. "I shall tell you something that you will not agree. "
"Why will we not agree" I asked.
"Because the science and mathematics you know are not correct，"he said. "You believe there are only three dimensions(三维空间)-length, breadth(宽)and thickness. "
"There is nothing to agree with that, " the youngest member of our little group said.
"Exactly! " the time traveller answered. "But there is also a fourth dimension-time. "
"We all know about time, " another member of the group said. "Time passes. "
"I do not agree, " the time traveller said. "Length, breadth and thickness do not pass. They stay in the same place in space. We move about them. I can prove that time is the same. It does not pass. We move in time the same way that we move in length, breadth and thickness. "
None of us believed the time traveller, and we argued with him for many hours.
"If we could travel back in time, " the scientist said." We could do things to change the future."
"If we could travel forward in time," the doctor(博士)said. " We could do things that change our present. "
The time traveller smiled. "It is clear, " he said. "That there is only one way I can show you that I am right. We must do an experiment. Please wait here.”
He left the room and soon returned, carrying what looked like a clock.
"This is a model of a time machine. It took me two years to make it，" the time traveller said. "I want all of you to understand that when I start the machine, it will immediately travel in time and disappear from present. "
He turned to the youngest of us. "Give me your hand，" he said.
The young man put out his hand. The time traveller took it and placed it on the machine.
Immediately, there was a sudden wind, and the little machine disappeared.
I was certain this was not a trick, but the doctor was not so sure
"Are you asking us to believe, " he said. "That the machine is now in the different time"
"Certainly! In my laboratory, a full-sine machine is almost complete. As soon as it is complete, I shall send myself on a journey through time. Would you like to see my machine?"
"Are you serious about this?" the doctor asked.
"I have never been more serious about anything, " the time traveller said. "Come. "
We followed him to his laboratory. There, we saw the actual machine，not quite complete, but large enough for a man to sit in.
34. How long did it take the time traveller to make his model time machine?
A. Two years. B. Two months. C. Twenty years. D. All his life.
35. Which is the right order of what happened in the story?
a. The model time machine disappeared with a wind.
b. The time traveller came back to the room with a model time machine.
c. The members of the group argued with the time traveller for many hours.
，我们将会及时处理。
