30 UK Grammar Questions That Sound Easy – Until You Actually Try Them

A fronted adverbial is very specific, though, to be fair. It's when the adverb is moved to the beginning of the sentence instead of immediately following the verb ("The door opened slowly" is a sentence in regular form; "Slowly, the door opened" is the same sentence in fronted adverbial form.) It's not a sin to NOT put a comma after the fronted adverb, but it IS generally accepted as proper grammatical/technical form. I was an English major and got my degree in English/Creative Writing, so maybe I remember this stuff more clearly than others, but it's something we were taught. For clarity and technicality's sake, one should put a comma after a fronted adverbial. Otherwise, the sentence can look like a run-on sentence - "Before dawn Kohl jumped on Lakota's kidneys to wake her up" vs. "Before dawn, Kohl jumped on Lakota's kidneys to wake her up." It's a fiddly thing, but it's legitimate and is actually grammatically/technically correct to have a comma after a fronted adverb.