----Did you open the door?---Yes. I remembered it before you arrived.A. openingB. being

问题补充：

----Did you open the door?

-----Yes. I remembered it before you arrived.

A. opening

B. being opened

C. to open

D. to have opened

答案：

(答案→)A. opening

B. being opened

C. to open

D. to have opened

解析：动词用法辨析。Remember to do sth记得要做某事；remember doing sth记得做了某事；句意—你把窗户打开了吗？—是的。我记得在你来开之前我记得打开了。