Question

Henry always forgets things he has done. Yesterday he forgot__________ and looked for it everywhere

1. A.
   to post the letter
2. B.
   to have the letter posted
3. C.
   to have posted the letter
4. D.
   having posted the letter

Answer 1

D
考查动词用法。regret后跟不定式一般式表示对即将发生的事感到遗憾，跟动名词或不定式完成式都表示对做过的事感到遗憾。选D。