I remembered the door before I left the office but forgot to turn off the lights.A. lock

问题补充：

I remembered the door before I left the office, but forgot to turn off the lights.

A. locking

B. to lock

C. having locked

D. to have locked

答案：

A. locking

(答案→)B. to lock

C. having locked

D. to have locked

解析：考查不定式做宾语，remember to do记得去做…,remember doing记得做过…，句意：我记得离开办公室要锁门，但忘了关灯。选B。