根据句意从括号中选择恰当的介词填空

1. I go to school __________(at / on) 7:30 every morning.

2. The doctor would like to meet her __________(between / among) 8:00 and 9:00 tomorrow morning.

3. -When did Hong Kong return to China?

    -__________(In / On) July 1st, 1997.

4. In the West, there is lots of excitement __________(in / on) Christmas morning when children get up

    very early to open their presents.

5. The Smiths have lived in China __________ (for / since) five years.

伸入液体中的开口玻璃管由于表面张力作用而产生内外液面的高度差与管径（），与液体的种类有关。

A.成正比

B.成反比

C.无关

D.相等