倒裝句是一種把動詞（助動詞）移動到主語前，起到強調、增強清楚與簡潔性功能的句子。
一、比較級倒裝
Girls like cats more than boys, who as a rule are a cruel lot, do.
這一句中修辭不佳，句尾的do無法省略，否則句子有歧義，但是這個助動詞離它的主語boys又太遠了。我們使用倒裝：
Girls like cats more than do boys, who as a rule are a cruel lot.?
總結：比較級使用倒裝
1> 從屬從句中的助動詞或be動詞不宜省略；
2> 主語后面有較長的修飾語。
二、關系從句的倒裝
關系詞必須先向前移動照成順序反常的時候才使用倒裝
句1：The President is a man.
句2：A heavy responsibility, whether he likes it or not, falls on him.
兩句聯合：
The President is a man on whom a heavy responsibility whether he likes it or not, falls.
on whom是一個介詞短語修飾falls，但是 移動到句首以后同falls的距離相隔太遠了，同時falls的主語a heavy responsibility同falls的距離也太遠，就需要使用倒裝句：
The President is a man on whom falls a heavy responsibility whether he likes it or not.
注意：如果關系詞原本就在句首的位置，沒有移動，就不能使用倒裝。
三、假設語氣的倒裝
假設語氣往往是使用if引導的，如果有be動詞和助動詞就可以將其移動到主語前面，省略連接詞。形成倒裝：
If I had been there, I could have done something to help.
為了加強簡潔形成倒裝：
Had I been there, I could have done something to help.
四、引用句的倒裝
直接引用：
The police said, "None was killed in the accident."
將引用的話放于前面，起到強調的作用：
"None was killed in the accident." said the police.
間接引用：
The WHO warns that cholera is coming back.
將最重要的放在前面，形成倒裝：
Cholera, warns the WHO, is coming back.
五、地方副詞倒裝
這種倒裝是把地方副詞放于句首，起強調作用。
There goes the train!
Here is your ticket for the opera!
這里是把there和here地方副詞放于句首的倒裝。其他的地方副詞也可以：
In Loch Ness dwells a mysterious monster.
六、否定副詞開頭的倒裝
表示否定的副詞（not、never、hardly、barely）放于句首強調語氣，就得使用倒裝
We don't have such luck every day.
如果把not every day放于句首強調不是每一天，就得使用倒裝：
Not every day do we have such luck.
另外有一些副詞hardly、barely移動到句首也要使用倒裝：
I had hardly sat down to work when the phone rang.
將hardly移動到句首起加強語氣的作用：
Hardly had I sat down to work when the phone rang.
注意：如果hardly在句首是正常的修飾詞，而不是起強調作用的，就不能使用倒裝句。
not only……but also配合形成倒裝就比較復雜，我們相信說明一下：
He not only passed the exam but also scored at the top.
not only……but also形成句子要求對仗工整，我們先來嘗試一下：
Not only did he passed the exam but also scored at the top.
前半句not only引導的從句我們改成了倒裝，但是與后面but also的句子不對稱，我們修改成：
Not only did he passed the exam but also he scored at the top.（不佳）
我們經常將not only和but also連在一起背誦，但是不知道only和also都是焦點副詞，有一種強調的功能。這時候就應該拆開but also，使得also強調后面的scored at the top：
Not only did he passed the exam but he also scored at the top.?
