句首由否定或半否定意义的副词或词组开头的句子。 这类词或短语主要有never, neither, nor, little, no, seldom, rarely, hardly, scarcely, no sooner, not only, in no way, at no time, few, not, by no means等, 如: Not a word did I say to him.Never have I found him so happy. I can't swim. Neither can he.No sooner had he gone to bed than he fell asleep.