Most of us think that people are the most important things on Earth., but we aren’t. We are really much less important than plants! If all the people on Earth die tomorrow, life will not stop. The plants, animals and everything else will go on living. But, if all the green plants die, Earth will become a very different place. The air will change and neither animals nor people will be able to live in that air.

All living things need plants to make the right kind of air. But they also need them for something else---food. Living things need food to grow, but only plants can make their own food. Green plants get light from the sun and water from the ground and turn it into food. Nothing else can do that!

10. We are hungry, I would like a bowl of rice, _____ my mother would like some dumplings.

　　　　　　 A. when 　　　　　 B. as 　　　　　　　　　　 C. while　　　　　　　　　　　 D. since

9. Mother was cooking _____ I left home.

　　　　　　 A. when　　　　　　 B. while　　　　　　　　 C. because　　　　　　　　　 D. until

8. Paul comes from Canada, _____ he can speak very good Chinese.

　　　　　 A. if 　　　　　　　　　 B. so 　　　　　　　　　　　 C. but 　　　　　　　　　　　 D. because

7. If you don’t hurry up, _____ you’ll be late for the meeting.

　　　　　 A. and　　　　　　　　 B. or 　　　　　　　　　　 C. so 　　　　　　　　　　　　　 D. but

6. You must eat less food and take more exercise, _____ you’ll be very fat.

　　　　　 A. but 　　　　　　　 B. and 　　　　　　　　　 C. so 　　　　　　　　　　　　　 D. but

5. Would you like rice _____ noodles?

　　　　　 A. or 　　　　　　　　 B. but　　　　　　　　　　 C. because　　　　　　　　　 D. so

4. The ground must be just right, _____ too wet _____ too dry.

　　　　　 A. either, or　　　 B. both, and　　　　　 C. between, and 　　　 D. neither, nor

3. The students should know _____ what _____ why.

　　　　　 A. so, as 　　　　　 B. both, and 　　　　 C. either, or 　　　　　　　 D. neither, nor

2. It was late. She took off her clothes _____ went to bed.

　　　　　 A. or 　　　　　　　　 B. so 　　　　　　　　　　　 C. and 　　　　　　　　　　　 D. but