句型如下： so +形容词/副词+be/助动词/情态动词that +从句。
Light travels so fast that it is difficult for us to imagine its speed.
= So fast does light travel that it is difficult for us to imagine its speed.
So easy was the work that they finished it in a few days.

7. done做形容词在句中做表语时，常把表语放在句首，要用倒装句式。
Gone forever are the days when the Chinese people had to use foreign oil.

8. 否定副词not , never, seldom, nowhere, little , rarely 放于句首时要用倒装句式。
We seldom get up at four in the morning.
= Seldom do we get up at four in the morning.
Not a single word from him could the enemy drag.
Rarely have I heard of such a silly thing.

9. hardly…when; scarcely…when…; no sooner…than… 可以用正常语序 had hardly done when… did 或用倒装句式Hardly had + 主语+ done when… did 句式。
hardly所在的句子用过去完成时。
The bell hardly had rung when the class began.= Hardly had the bell rung when the class began.
No sooner had he arrived in Beijing than he began to work.

10. not only… but also 如连接两个成分时，不用倒装；连接句子时，前面的句子要用倒装。
Not only was everything that he had taken away from him, but also his German citizenship.
Not only is he busy, but also I have a lot of work to do.
Not only does he speak English very well, but also he speaks French well.

11. only 及所修饰的副词、介词短语或状语从句放在句首时，要用：
only+ 状语+ be /助动词/情态动词+主语及其他
Only when he told me the news did I know what had happened.
Only in this way can you make progress in your English.

12. 虚拟语气中的倒装句
If I were you, I would take the job. = Were I you, I would take the job.