否定句的构成

　　⑴如果谓语动词中含有be动词、情态动词、助动词，则在这些词后直接加not构成否定（可缩写）。如：Simon is playing football. He hasn’t been to Beijing.
 

　　⑵如果谓语动词只由行为动词构成，则在行为动词原形前加上don’t/doesn’t/didn’t构成否定。如：I don’t have lunch at home.
　　⑶有些词本身表示否定意义，是否定词，如：no, nothing, nobody, no one, never, neither, none, few, little, hardly等。如：There is little water in the glass, is there?
　　⑷有些情态动词的否定形式较为特殊，如：may的否定式可以是may not，can’t或mustn’t；must的否定式可以是can’t，needn’t或mustn’t等。如：—Must I go now?—No, you needn’t. You may go after class.
　　⑸have/has/had作“有”讲时，其否定式可以在其后直接加not构成否定形式。如：I don’t have a motorbike. I haven’t a motorbike.
　　⑹had better do sth.的否定形式是：had better not do sth.。如：We had better not talk in class.
　　⑺如果主句是I think/guess/believe，其后的宾语从句表示否定，常将否定词提前到主句中。如：I don’t think chickens can swim.
　　⑻复合句的否定一般是否定主句。如：What he said didn’t make me sad.
　　⑼特殊的否定：①some →no或not any（非主语）。如：Some girls have been to the park. →No girls have been to the park. ②both…and…→neither…nor…。如：Both my father and my brother help. →Neither my father nor my brother helps. ③a few →few。如：There are a few apples on the table. →There are few apples on the table. ④a little →little。如：There’s a little milk in the bottle. →There’s little milk in the bottle. ⑤too(也), also→(not…)either。如：I’m a teacher, too. →I’m not a teacher, either. ⑥already→(not…) yet。如：The teacher has already gone home. →The teacher hasn’t gone home yet. ⑦and（非主语）→or或and no/not。如：It has a mouth and a nose. →It doesn’t have a mouth or a nose.⑧ all →none（全部否定）；not all/all…not（部分否定）。如：All of the students have gone to the park. →None of the students have/has gone to the park.→ Not all of the students have gone to the park.⑨both →neither（全部否定）；not both/both…not（部分否定）。如：Both of my parents are teachers. →Neither of my parents is a teacher.→ Both of my parents aren’t both teachers.⑩always →never（全部否定）；not always（部分否定）。如：Wang Lin is always late for school. →Wang Lin is never late for school.→ Wang Lin isn’t always late for school. ⑾each (pron.) →none/nobody/neither（全部否定）；not each/each…not（部分否定）。如：Each of them has a basketball. →None of them has a basketball. →Each of them doesn’t have a basketball. ⑿each(adj.) →no/neither（全部否定）；not each（部分否定）。如：Each boy has a basketball. →No boy has a basketball. →Not each boy has a basketball. ⒀every → no（全部否定）；not every/every…not（部分否定）。如：Every boy has a basketball. →No boy has a basketball. →Not every boy has a basketball.