— Look the light in the living room is still on. —Oh I forgot .A. turning it offB. turn

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。