招标投标是合同的( )，它对合同的整个生命期有根本性的影响。
A．形成阶段
B．发展阶段
C．过渡阶段
D．实施阶段
参考答案：A
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.
咽鼓管具有什么功能？
