题目内容：

英语 求教4道关于倒装的题.
1.So absorbed ___ inher work that she didn't realize it was time that she picked up her daughter.
A.was she b.did she
我想问下A,b两项选项均为倒装,但是各有什么不同啊,应该选哪个?
2.I suddenly foundmy watch didn't work any more and only then ___ I was late for school.
A.did Irealize b.had i realized
我知道空中填部分倒装的格式,我认为 我意识到我迟到在前,发现手表在后,故意识应该是过去的过去（也就是发现手表坏了）的时候发生的,应该选择had done的结构啊,但是为什么答案是didi realize?
3.Not a singleword ___ at the beginning of the meeting yesterday.
A.has he said b.did he say
A,b两项应选哪个?区别是什么啊?不都是过去说的吗?
4.Over theChangJiang river ___ four bridges in Wuhan by now.
A.have beenbuilt b.has been built
这个建造built应该说的是主语,这句话主语是长江,长江怎么能建造或是被建造呢?应该把四座桥放到前面当主语啊?