Question

You'd better ________ when you come in.

1. A.
   not to wake him up
2. B.
   not wake him up
3. C.
   to not wake him up
4. D.
   not waking him up

Answer 1

B
解析：
had better是复合情态动词，后面只能跟不带to的不定式；
其肯定或否定意思是通过不定式的肯定或否定形式来表达的，表示否定意思时，在不定式前加not。