用所给单词的适当形式填空。

1. I think this song is _____ (popular) than that one.

2. There are some _____ (different) between us.

3. You speak English as _____ (good) as Tom.

4. Ruth isn't as _____ (clever) as her best friend.

5. I have ______  (many) books than you.

当镗刀刀尖高度高于被加工孔的中心时，会使切削时镗刀前角（）。

A.不变

B.不稳定

C.减小

D.增大