1、当句首状语为否定词或带有否定意义的词语时，这个句子就需要部分倒装 这类词语有hardly, scarcely, rarely, seldom, never, few,little, less, at no time, by no means, in no case, under no circumstance, in no way,on no account, on no consideration, no longer, not only等。 eg. He never smokes. 他从来不抽烟。 Never does he smoke. eg. Not only did the customer complain about the food, he also refused to pay for it. 这位顾客不仅仅 抱怨食物不好，还拒绝付费。 eg. 在任何情况下我都不会相信你。Under no circumstance do I trust you.
2、当句首为only加状语的时候，这个句子需要部分倒装。 eg. Only with you can I feel happy. eg. 只有当你来了这，我们才可以开始会议。 Only when you come, can we start the
3、so......that 结构中的so位于句首时，常引起部分倒装 eg. He runs so fast that I can't catch up with him. 他跑得实在是太快了，以致于我 都没有办法追上他。 So fast does he run that I can't catch up with him. eg. The moon was so bright that the flowers bright as by day. 皓月当空，花朵就像白天那样的鲜艳。 So bright was the moon that the flowers bright as by day.
4、句子开头的as 处在第二个单词的位置上，表示虽然的意思。 eg. Although I am young, I can live by myself. 虽然我很小但是我却能养活自己了。 Young as I am, I can live by myself. eg. Although she is a girl, she can support the hole family. 虽然她是个女孩，但 是她却可以养活整个家庭的人。Girl as she is, she can support the hole family. eg. Although I like music very much,.... Much as I like music,.....
5、常见的固定搭配结构中需要用倒装的情况。 hardly.....when.... 一......就...... scarcely .....when..... hardly，scarcely 后面一定要用过去完成时，when 后面用一般过去时。 eg. Hardly had he seen me when he ran away. 他一看到我就跑开了。 eg. Hardly had the baby cried when his mother rushed to carry him. 婴儿一哭，他妈妈就跑去抱他。 no sooner....than..... 一......就...... no sooner 后面一定要用过去完成时，than 的后面用一般过去时。 eg. No sooner had they reached home than it rained more and more heavily. 他们一到家，雨就越下越大起来。 the more ......the more... 越....越.... eg. The harder you work, the happier you feel. 你工作越努力，就越觉得快乐。
__________ your address，I would have written to you.
A. Did I know B. Were I to know
C. Had I known D. If I should know
此题应选 C。这是虚拟语气的倒装形式。当虚拟条件句中含有 were，had，should，could等动词时，可以将if省略，然后将 were，had，should，could 等词移至句首：
1. If he should fail，he would kill himself.
→Should he fail，he would kill himself.
2. If I were you，I would do it at once.
→Were I you，I would do it at once.
3. If I could do it，I would.
→Could I do it，I would.
4. If he had seen you yesterday，he would have asked you about it.
→Had he seen you yesterday，he would have asked you about it.
If he had money，he would buy a car.
→Had he money，he would buy a car.