日期:2011-01-19 10:15
主語從句
Whether it will do us harm or good is hard to say.
Why he did it remains a puzzle.
It’s not yet known whether there is a show tonight.
嵌套語句作為說明語：表語從句
My impression is that they are satisfied with your explanation.
統(tǒng)指所。。。。。。的：what 從句用作表語
This is what he did.
That’s what I know.
所。。。。