In formal style, adverbs with negative meanings, such as never, rarely, rarely, almost, almost, soon, no longer, nowhere, etc. , if located at the beginning of the sentence, should be inverted in the latter part:

I will never forgive him. /I will never forgive him. I will never forgive him.

pay attention to

(1) For the not…until sentence pattern, when not until… is at the beginning of the sentence, the main sentence behind it should be inverted:

He didn't leave the room until the rain stopped. He didn't leave the room until the rain stopped.

(2) Some prepositional phrases that act as adverbs, because they contain negative words, will be partially inverted if they are located at the beginning of the sentence:

This switch must not be touched. This switch must not be touched.

The inversion of "only+ adverbial" at the beginning of a sentence

When an adverbial is only modified by an adverb and placed at the beginning of a sentence, it is followed by a partial inversion:

Only then did he realize that he was wrong. Only then did he realize that he was wrong.

The inversion of "so+adjective/adverb" at the beginning of a sentence

The adverb so is followed by an adjective or adverb at the beginning of the sentence, followed by a part inversion:

It was so cold that we had to stay at home. It was so cold that we had to stay at home.

"So+Auxiliary Verb+Subject" Inverted

When you want to show that some of the affirmative situations mentioned above also apply to the latter, you usually use the inverted structure of "So+ auxiliary verb+subject":

You are young, I am young, you are young, I am young.

pay attention to

(1) If a negative situation is put forward in front to show that the latter also belongs to the same negative situation, then the so in it should be changed to never or nor:

You are not young, and neither am I.

She hasn't read it, and neither have I. She hasn't read it, and neither have I.

(2) Pay attention to the difference between this structure and the "so+ subject+special verb" structure that expresses emphasis or agreement:

"It was very cold yesterday." "Sure enough." "It was very cold yesterday." "It's really cold."

A flip caused not only by ... but also by ...

When not only … but also at the beginning of a sentence, the sentence is usually partially inverted not only after:

He is not only a teacher, but also a poet. He is not only a teacher, but also a poet.

Ellipsis and inversion of subjunctive conditional sentences

If-guided subjunctive conditional sentences contain had, were, should, etc. If if is omitted, had, were, should, etc. It should be moved to the front of the subject to form an inverted sentence:

If you had come yesterday, you would have met him. If you had come yesterday, you would have met him.

Note that the early had after omitting if is not necessarily an auxiliary verb:

If I had money, I would buy it. If I had money, I would buy it.