在以下情况下，英语中的句子需要倒装：

1、 表示否定意义的短语或从句位于句首时，主句中的谓语动词需要倒装。例如：

Never have I seen such a beautiful flower.

2、 当以“soeitheror”开头的句子描写前面的情况时，主句中的谓语动词需要倒装。例如：

He is so kind that we all like him.

3、 在某些条件句中，当“if”引导的从句位于句首时，主句中的谓语动词需要倒装。例如：

Were I rich, I would travel around the world.

4、 在某些表示时间的状语位于句首的句子中，主句中的谓语动词需要倒装。例如：

At six o'clock, the bell will ring.

5、 在某些以“only”开头的句子中，主句中的谓语动词需要倒装。例如：

only when he arrived did he realize his mistake.

6、 在某些以“soeitheror”开头的句子中，主句中的谓语动词需要倒装。例如：

So far has he completed the task.

7、 在某些以“never/seldom/hardly/scarcely”开头的句子中，主句中的谓语动词需要倒装。例如：

Hardly had he arrived when the phone rang.

请注意，这些倒装情况可能因语境而有所不同，因此在实际利用中可能需要根据具体情况进行调剂。

为了让您更深入了解，

装句分全倒装句和半倒装句.

全倒装:主语与谓语交换位置不需任何助动词,叫全倒装.全倒装有以下三种情况:

1、当here,there,out,in,up,down等副词放在句首时,句子需全倒装:

There goes the bell!铃响了!There lived an old man.Here comes the bus.注意：

①在这种情况下倒装仅限于不及物动词或be动词,像go,come,mush等.②主语如果是代词时不需倒装如Away he went.他走远了.

2、方位状语在句首,如:

In front of the house stopped a police car.

Nearby were two canoes in which they had come to the island.

Under the tree sat a boy.

3 、直接引语在句首,这种情况可倒装也可不倒装

"What does it mean" asked the boy或the boy asked.

半倒装:主语与谓语的助动词交换位置称半倒装,有以下数种情况:

1,否定意义的词在句首,句子半倒装,例如:little,never,not,no,hardly,rarely,seldom

Never shall I forget you.At no time was the man aware of what was happening.

Little did I understand what he said to me at that time.

2、 几对并列连词如not only…but also,hardly… when等连接两个并列句,连词在句首,前句半倒装,后句不倒装:

Not only was everything he had taker away from him,but also his German citizenship was taken away.

No sooner had I got to the bus stop than the bus started.

注意：

①not only…but also连接两个并列主语时不需倒装,如:Not only you but also I like playing chess.

②neither…nor在句首时,前后两句都需倒装,Neither do I have a sister nor does my husband.

3、only在句首强调状语,主句半倒装:

only then did I realize that I was wrong.only in this way can I learn from my fault.

only when the war was over in 1918,was he able to get back to work.

注意:only强调主语不倒装:only the teachers can use the room.

4、so…that句型,so在句首时,主句倒装,that从句不倒装:

So easy is it that a clild can learn it.So hard did he work that he finally won the fame.

I saw the film,so did he.

5.省略了if的虚拟条件句

Had I been informed earlier,I could have done something.Were she here,she would support the motion.