问题补充：
----The light in the office is still on.
----Oh, I forget .
A. turning it off
B. to turn it off
C. turning off it
D. to turn off it
答案：
A. turning it off
(答案→)B. to turn it off
C. turning off it
D. to turn off it
解析：考查动词用法。Forget to do sth忘记要做某事；forget doing sth忘记做了某事；根据句意办公室的等还亮着，说明我忘记关灯了，用forget to do sth忘记要做某事。当动词后面是副词的时候，如果宾语是名词，则把名词放在动词与副词之间或者放在副词的后面都可以。如果宾语是代词，则要把代词放在动词和副词之间。本题得it是代词，则放在turn与off之间。故B正确。
