Question

I’m sorry. I forget ________ it when I left.

A. locking
B. locked
C. to be locked
D. to lock

Answer 1

答案D
forget的基本用法有两种：即forget to do something和forget doing something前者意为“忘记了应该做的事”，而后者意为“忘记了已经做过的事”。句子的题意指“当我离开时忘了锁门”显然此题指的是“忘记了应该做的事”。