词汇运用：根据所给句子的意义及首字母或中文提示写出正确的单词。

1. It is polite to help those who are in t            .

2. There is no d             that computers are widely used in all kinds of areas.

3. Trees can p             the wind from blowing the earth away .

4. She is w              in English, let's try our best to help her improve it.

5. Liuxiang is regarded as our national h             .

6. Make sure that all               (垃圾) should be put into the dustbin.

7. We should learn a lot and master some               (基础的) skills when we are learning.

8. Computers are used in business to place and                (删除) orders .

9. When a child makes a little progress in studying , we should               (表扬) him for it.

10. What's the                (人口) of Laibin City? It's more than 2,450,000.