问题补充:
— Look, the light in the living room 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:
A. turning it off
B. turn it off
(答案→)C. to turn it off
D. having turned it off
解析:句意:——看,客厅里的灯还亮着。——哦,我忘了关灯。forget doing sth.对做过的事忘记了。forget to do sth.忘了去做某事。根据the light in the living room is still on.可知灯还亮着,因此忘了去关灯。
故选C。