what surprised me a lot was that he didn't know _____ the difference between "say" and "speak" lay.

问题描述:

what surprised me a lot was that he didn't know _____ the difference between "say" and "speak" lay.
A what B that C where D which
,为什么啊,lay在这里是什么意思

选BD的话没有先行词,不正确.lay在这里是'在'的意思,为不及物动词,不能直接加宾语,只能选C.