1) 句首为否定或半否定的词语,如no, not, never, seldom, little, hardly, at no time, in no way, not until… 等。 Never have I seen such a performance. Nowhere will you find the answer to this question. Not until the child fell asleep did the mother leave the room. 当Not until引出主从复合句,主句倒装,从句不倒装。