Question

I’m sorry        written you a letter at the tine.

A. to have not

B. to not have

C. not to have

D. not having

Answer 1

C

考查不定式的完成时。句意“对不起那时没给你写信。”sorry后跟动词不定式，排除D；不定式的否定是在to前加not，排除A、B。故选C。