Inversion: "I didn't realize how useful English was until I went to the UK."
Not until I went to the UK did I realize how useful English was.
Inversion "Hermione Granger rarely misses a chance to show off."
Rarely does Hermione Granger miss a chance to show off.
Inversion ¨I had just started watching the movie when the lights went out"
Hardly had I started watching the movie when the lights went out.