4. F
5. G
6. B
7. J
8. D
9. H
10. I

四、
1. C
2. C
3. B
4. A
5. B

五、
A: Our school is beautiful, isn't it?
B: Yes. To make our school more beautiful, we should keep our school clean.
A: What can we do to keep it clean?
B: We can sweep our classroom everyday.
A: That's right ! We should stop throwing rubbish on the ground,too.

4. F
5. G
6. B
7. J
8. D
9. H
10. I

四、
1. C
2. C
3. B
4. A
5. B

五、
A: Our school is beautiful, isn't it?
B: Yes. To make our school more beautiful, we should keep our school clean.
A: What can we do to keep it clean?
B: We can sweep our classroom everyday.
A: That's right ! We should stop throwing rubbish on the ground,too.