用所给词的正确形式填空。

1. They can plant _____ ( hundred) of trees every year.

2. —Is Beijing _____ ( hot) than Wuhan？

    —No, it isn't.

3. the building here is rnuch _____ ( high) than that one.

4. Washington D. C. and New York are big _____ (city) on the east coast of the USA.

5. The town _____ ( have) a population of 2 thousand people.

6. An elephant is _____ ( heavy) and _____ ( strong) than a sheep.

7. My classroom is bigger than _____ ( she).

8. Which problem is _____ ( easy), this one or that one?