［特殊詞精講］forget doing/to do
forget to do 忘記要去做某事，forget doing 忘記做過某事。例如：
The light in the office is stil on. He forgot to turn it off. 辦公室的燈還在亮著，他忘記關了。(沒有做關燈的動作)
He forgot turning the light off. 他忘記他已經關了燈了。(已做過關燈的動作)
典型例題
---- 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 可知燈亮著，即關燈的動作沒有發(fā)生，因此用forget to do sth.而forget doing sth表示燈已經關上了，而忘記了這一事實。此處不符合題意。
