從來不/沒…grammar point · tier 2 · 從來不/沒 — never once across the whole stretch of past time
Sweeps the entire span of past time up to now: across all of it, not once — 不 for a standing habit (never does), 沒 for completion (never has, paired with 過).
從來不 sweeps the whole past habit (never, as a rule); bare 不 bars the present or future instance. 我從來不喝酒 = I have never drunk, ever; 我不喝酒 = I don't drink (now / this time).
從來沒…過 widens 過 to the entire span (never once in a lifetime); bare 沒…過 says only that it has not happened yet. 從來 is the span; 過 is the experiential aspect riding inside it.
從來沒 sweeps the whole record (not once, ever); bare 沒 negates one completed event. 從來 picks the negator by habit vs record, the same split as 不 vs 沒, then stretches it back over all of time.
habit with 沒: 我從來沒喝酒 → 我從來不喝酒（standing habit takes 不）
experience without 過: 他從來沒搭飛機 → 他從來沒搭過飛機（沒-span needs 過）
single recent event with 從來: 我從來沒吃早餐（this morning） → 我今天沒吃早餐（從來 is for the whole past, not one morning）
English 'never' covers both the habit ('never drinks') and the experience ('have never flown') with one word, so learners pick the wrong negator after 從來; 不 for the standing habit, 沒…過 for the lived record.