英语的正常语序是-主语+助动词/动词。
倒装一般将助动词/动词放在主语的前面。
1.最常见的倒装句型就是疑问句，比如
原句是 ： You are tired. 疑问 Are you tired ?
2. 在有些情况下，我们会在非疑问句里运用倒装结构，达到强调等目的。
2.1 当否定的词在句首的时候， 往往用倒装结构。
比如 Hardly , Never, Seldom , Rarely , Only then, Not only .. but , Not sooner
Scarecely , Only later, Nowwhere ,Little , Only in this way, in no way , on no account.
例句： Hardly have i seen a sunny day in last month.Seldom do we meet each other after graduation.
Noon sooner had i drove away than the police gave ticket for illegal parking.
Nowwhere could i found the PSP.
Only in this way could you get long-lasting happniness.
In no way do i agree with what you are saying.
On no account should vendor switch material without our consent.
2.2 当以下词组在句首的的时候， 从句用倒装结构
Not until, Not since, only after, only when, only by
例句：Only by working extremely hard could we afford a house.
2.3 可以用倒装来替代 If条件从句里的"If"
正常语序： If i had checked careflly , this problem wouldn't have happened.
倒装语序： Had i checked carefully , this problem wouldn't have happened.
正常语序： I we had discovered it sooner , we could have prevented the tragedy!
倒装语序： Had we discovered it sonner , we could have prevented the tragedy!
2.4 当状语在句首的时候， 要将助动词/动词提到主语的前面
正常语序： All the money we had lost was on the table.
倒装语序： On the table was all the money we had lost .
正常语序： The knights came around the corner.
倒装语序： Round the corner came the knights.
2.5 当句子以 SO+形容词开头的时候，可以用倒装
正常语序： The girl was so beautiful that nobody could talk of anything else.
倒装语序： So beautiful was the girl that nobody could talk of antying else .
2.6 There开头的句子可以倒装
正常语序： A lake lies near our village.
倒装语序： There lies a lake near our village.
正常语序：A great thicker named Aristotle lived in greece.
倒装语序：There lived in greece a great thicker named Aristotle.
2.7 当"Only +状语“在句首标示强调的时候，要用倒装
正常语序： I only finished the book yesterday.
倒装语序： Ony yesterday did i finish the book.
2.8 当Often , always , once, many a time , now and then , everyday 等表示频度的副词及短语放在句首的时候，要倒装
正常语序： We often warn them not t odo so.
倒装语序： Often do we warn them not to do so.
2.9 由 As, however 引导的让步状语从句，可以倒装
正常语序：I will not buy it though i like it .
倒装语序： Much as i like it , i will not buy it.
正常语序： He continued the work despite he was tired.
倒装语序： Tried as he was , he continued the work