问题补充:
--Excuse me, I don think you can smoke here.
---Really sorry. I this is a non-smoking room.
A. didn know
B. don know
C. have no idea
D. haven known
答案:
(答案→)A. didn know
B. don know
C. have no idea
D. haven known
解析:考查时态:句子的意思是:——打扰一下,先生,这是禁烟室。——抱歉,我不知道这是禁烟室。“我不知道这是禁烟室”应该是发生在过去的事情,所以使用一般过去时即可。选A。