Inversion

N -> AUX -> sub/V

In formal English, especially in writing, we sometimes change the normal word order to make the sentence more emphatic or dramatic.

1 Not only is the plot great, (but) it’s also very well written. Not until you can behave like an adult will we treat you like an adult. Never have I heard such a ridiculous argument. Never again will I believe a word he says. No sooner had the football match started than it began to snow heavily.

This structure is common with negative adverbial expressions such as Not only…, Not until…, Never (again)…, and No sooner… (a formal way of saying as soon as). When we use inversion after the above expressions, we change the order of the subject and (auxiliary) verb. NOT Not only the plot is great…

Compare:

I have never heard such a ridiculous argument. (= normal word order) Never have I heard such a ridiculous argument. (= inversion to make the sentence more emphatic)

2 Not only did you forget to shut the window, (but) you also forgot to lock the door! Not until you become a parent yourself do you understand what it really means. In the present simple and past simple tense, rather than simply inverting the subject and verb, we use do / does / did + subject + main verb. NOT Not only forgot you to shut the window…

3 The train began to move. Only then was I able to relax. Only when you leave home do you realize how expensive everything is. Hardly had I sat down when / before the meeting began. Rarely have I met a more irritating person.

Inversion is also used after the expressions Only then…, Only when…, Hardly / Scarcely…, Rarely…

Overuse of inversion

Inversion should only be used occasionally for dramatic effect. Overusing it will make your English sound unnatural.

examples

For not only is necessary inversion Avoid to use IF

I dindt learn this until I started University Not until I started university did I learn this

Children only stop believing in Santa when they get older Only when get older do they stop blieving in Santa

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