forget doing sth怎么用

forget to do 忘记要去做某事。 (未做)
forget doing 忘记做过某事。 (已做)
The light in the office is stil on. He forgot to turn it off.
办公室的灯还在亮着，它忘记关了。(没有做关灯的动作)
He forgot turning the light off.
他忘记他已经关了灯了。 ( 已做过关灯的动作)
Don't forget to come tomorrow.
别忘了明天来。 (to come动作未做)

典型例题
---- The light in the office is still on.
---- Oh，I forgot___.
A. turning it off B. turn it off C. to turn it off D. having turned it off
答案：C。由the light is still on 可知灯亮着，即关灯的动作没有发生，因此用forget to do sth.
而forget doing sth表示灯已经关上了，而自己忘记了这一事实。此处不符合题意。

forget doing sth 忘了做过某件事
forget to do sth 忘了去做某件事

前者表示已做过，但后者表示还未做过

忘记已经做了某事的意思
i forgot closing the window
我忘了是否关了窗了

错了 应该是：FORGET TO DO STH 吧
人称＋FORGET TO DO STH +时间

表示已经做过某件事情,但是忘记自己曾经做过这件事.