Never have I …
RuleWhen a negative or limiting adverb (never, rarely, not only, seldom, hardly) begins the sentence, the subject and auxiliary invert, as in a question.
Curiosity
"Never I have seen" or "Never have I seen"? Why does it flip?
Intuition
Fronting a negative for emphasis triggers question-like order: auxiliary + subject. The emphasis pulls the auxiliary in front of the subject.
Visualization
See the parts: the fronted negative and the auxiliary after it are highlighted. The relation: "fronted negative → auxiliary + subject (inverted)."
A fronted negative triggers auxiliary + subject inversion.
Neverhavewefaced such growth
Essence
Triggers: never, rarely, seldom, hardly, little, not only (but also), no sooner (than), only then/after. Form: negative adverb + auxiliary + subject + main verb. If there is no auxiliary, add do/does/did (Rarely does he complain). Common in formal writing.
Examples
Never have we faced such a challenge.
Not only did sales rise, but profits also grew.
Rarely does the system fail.
Mini-quiz
"Rarely ___ such an opportunity arise." Which fits?