The auxiliary verb comes before the subject in several different structures. This is usually referred to as ‘inversion’.
Never have I seen such a mess!
Not only do I enjoy classical music, but I also have regular music lessons.
An inversion generally begins with a negative word or phrase.
If a negative adverb or adverbial expression is put at the beginning of a clause for emphasis, it is usually followed by auxiliary verb + subject.
Time expressions: never, rarely, seldom
These time expressions are usually followed by perfect verb forms or modal auxiliary verbs.
- Seldom have I seen anything more remarkable.
- Never have I seen such a vast crowd.
Time expressions: hardly, barely, no sooner, or scarcely
These time expressions are used to talk about two past events that happen one after the other.
- Hardly had she arrived, when problems started.
- Scarcely had I sat down when the doorbell rang.
- No sooner had he finished dinner, than he started feeling ill.
Sentences beginning with ‘only’ also follow an inverted word order.
- Only then did I understand what I had done.
- Only after her death was I able to love her.
Little is a negative word. Sentences beginning with little also have an inverted word order.
- Little did she understand what she was doing.
- Little did I realize the danger I faced.
Inverted Conditional Forms
In conditional clauses, an auxiliary verb can be put before the subject instead of using if.
- Were I you, I wouldn’t do it. (= If I were you, I wouldn’t do it.)
- Had I understood the problem, I wouldn’t have made those mistakes. (= If I had understood the problem, I wouldn’t have made those mistakes.)