根据句意和首字母提示填空。

1. What's this in E            ?

2. How do you s             pencil?

3. Call Jane a             635－2469.

4. Is this y             eraser?

5. My b           is big. I can put many things in it.

6. Is that your c           game in the case?

7. I want to buy two pencil s            .

8. A set of k              is on your desk.

9. Is your watch in the l              and found case?

10. He can't find the word in the d             .

简述小站间距与大站间距的特点及各自的缺陷。