用适当的介词填空。

1. Liu Hang sits _______ the right side of the classroom. Li Gang sits in the front.

    Zhang Xia sits next _______ him.

2. —Do you sit _______ the center of the classroom?

    —No, I sit on Meimei's right. We sit _______ the front now.

3. Look _______ the picture. There is a pig _______ it.

4. Can you see the blackboard _______ the wall?

    My teacher is drawing a tree _______ it.

5. There are some public phones _______ the street.

6. You can see the post office _______ the corner of the street.

7. There is a bird _______ the sky (天空).

8. My mother gets home _______ 6 o'clock every afternoon.