At that time I had no idea ________ I could hand it to him without being seen.

问题描述:

At that time I had no idea ________ I could hand it to him without being seen.
A.if B.how C.which D.that how
选B为什么不选D

have no idea= don't know ( 不知道 )
其后可直接跟特殊疑问词引导的陈述句.
译文:那时,我不知道怎样才能偷偷地将东西交给他.