Question

I would have come sooner ____possible,but I____that your were still waiting for me.

A.it were...didn't konw
B.were it ...hadn't know
C.it had been..wouldn't have known
D.had it been...didn't know.
答案是选D.
希望可以解释一下这句话的意思..和为什么选D...

Answer 1

had it been是if it had been的倒装形式.if条件句的虚拟语气都可以这么倒装并且省略if

这句话是明显的虚拟语气
主句would have done表示对过去的虚拟,因此条件从句也必需用对过去的虚拟,那么A和B都错(A,B是对现在的虚拟)
C,D中选择D就是因为上面说的倒装

后面but并列的一个句子则是通过转折进一步说明过去的情况:在那个时候我不知道你在等我.因为这个是真实的,所以用一般过去时didn't know

Answer 2

（过去）如果可能的话我当时就会早点来了，但是我那个时候不知道你是不是仍然等待着我

表示过去发生的事情，it had been表示虚拟语气

Answer 3

had it been .
HAD是提前了。在虚拟语气中had.were.should,could.(害的我输的苦得)
在用IF I *** ...（***表示以上4个词语）的时候可以提前。第一个空就是因为 原句应为 if it had been possible所以had提前，变成D选项的样子。后面的空是与现在时间相反，虚拟语气用过去时。
呵呵。