英语专四语法总结，本篇内容简介：倒装结构——以only修饰状语开头的句子，副词或短语开头的句子，让步从句的倒装等语法知识。
倒装结构
1.下列否定词及含有否定意义的词组修饰状语时，若置于句首，句子的主谓要部分倒装:never, no, neither, not only, hardly, scarcely, little, seldom, rarely, not until, nowhere, at no time, on no account, in no respect, in no sense, by no means, in no way, no longer, no less, no more, no sooner than, under no circumstances, in vain, still less。如：
Not only is its direct attack on their discipline, it bypasses the essence of what sociologists focus on.
Under no circumstances should we do anything that will benefit ourselves but harm the interests of the state.
2.以only修饰状语开头的句子，句子的主谓要部分倒装
Only when you have obtained sufficient data can you come to a sound conclusion.
3.以下列副词或短语开头的句子，句子的主谓要部分倒装
often, so, well, to such a degree, to such an extent, to such extremes, to such a point，many a time。如：
So involved with their computers do the children become that leaders at summer computer camps often have to force them to break for sports and games.
4.以下列副词开头的句子，句子的主谓要全部倒装
(1)出于修辞需要，表示方向的副词：out, down, in, up, away, on。如：
Down jumped the burglar from the tenth floor when he heard someone shouted at him.
(2)出于习惯用法：here, there, now, thus, hence, then。如：
Now is your turn. There goes the bell.
5.让步从句的倒装
(1)as引导让步状语从句，必须采用倒装结构，但不是主谓倒装，而是将被强调的内容置于句首。如：
Much as I have traveled, I have never seen anyone to equal her, in thoroughness, whatever the job.
(2)出现在句型be+主语+其他, come what may中。如：
Our civilization has accumulated an incredible amount of knowledge—be it scientific or artistic.
The business of each day, be it selling goods or shipping them, went quite smoothly. Come what may, I’ll be on your side.
6.比较从句的倒装
as, than引导的比较从句中，如果主语是名词短语且较长，经常采用倒装结构(不倒装也可以)。注意：这种结构主语一般为名词，如果是代词则不倒装。如：
Hydrogen burns much more cleanly than do other fuels and is easy to produce. Reading is to the mind as is exercise to the body.