英语，句子怎么变否定句？

英语，句子怎么变否定句？

先看句子里有没有be动词（am,is,are）、情态动词(can,may,would)，如果有，在这些词后面直接加not
如果没有，就在谓语动词前加don't,doesn't 或者didn't
例如：
He is a student. He isn't a student.
She can fly a kite. She can't fly a kite.
I go to school by bus. I don't go to school by bus.
He likes to play football. He doesn't like to play football.

先看句子里有没有be动词（am,is,are）、情态动词(can,may,would)，如果有，在这些词后面直接加not 如果没有，就在谓语动词前加don't,doesn't 或者didn't 例如： He is a student. He isn't a student. She can fly a kite. She can't fly a kite. I go to school by bus. I don't go to school by bus. He likes to play football. He doesn't like to play football

1. 主系表结构的句子，只需在系动词加not。如：He is\ wasa teacher --- He isn't\ wasn`t a teacher . 2. 主谓宾结构的句子，根据时态和人称用助动词适当形式加 not 。如： He\ she works hard ---He doesn't work hard .一般现在时态的第三人称单数，注意用 doesn't 其后动词要还原成原形。 They\ We \ you work hard -- They\ We \ you don't work hard 。 They\ We \ you\ He\ she worked hard -- They\ We \ you\ He\ she didn't work hard . 一般过去时态，注意用 didn't ， 其后动词要还原成原形。 3. 主语﹢情态动词﹢动词原形﹢句子其它成分。只需在情态动词后加 not 。如： He\ she\ we\ you\ They will(must,can,may,need,shall, shoud..) do it now ---He\ she\ we\ you\ They won't (must not,can not,may not,need not ,shall not, shoud not..)do it now . 4. 主语﹢has\have\had﹢done﹢句子其它成分.只需在has\have\had后﹢not。如： He has come back -- He hasn't come back They have finished the work ---They haven't finished the work We had finished the work before yesterday.---We hadn't finished the work before yesterday.

举例说明 1. He is a teacher ---He isn't a teacher 2.I am a teacher ---I am not a teacher 3. You are tall ---You aren't tall 4 He works hard ---He doesn't work hard 5 I word hard ---I don't work hard 6. He will do it now ---He won't do it now 7.He has come back --He hasn't come back 8. They have finished the work ---They haven't finished the work 9. He mustn't step into the door 10. You needn't do it now 11 I can't do it myself

一、陈述句：是用来陈述一件事情或表示一种看法，可分为肯定句和否定句两种形式。 1、谓语动词是be动词,助动词have, has, will,情态动词can等时，只要直接在这些词后面加not就构成否定形式。 eg. lily has already read this new book. (改为否定句) lily ______ ______ this new book ________. 2、谓语动词是行为动词而又没有助动词或情态动词时，必须在谓语动词前加助动词，一般现在时加助动词do ，第三人称单数加does，一般过去时加did，再和not构成否定结构。必须指出的是：don't, doesn't, didn't后都用动词原形。 eg.1)jill has lunch at school every day. (改为否定句) jill _____ _____ lunch at school every day. 2)the children had a good time at the party. (改为否定句) the children ______ _____ a good time at the party. 3)rose didn't drink any milk this morning.（改为肯定句) rose ______ ______ milk this morning. 二、疑问句：是用来提出问题的句子。 a.一般疑问句：以be动词, have /has/do等助动词、can/may等情态动词开头，以yes或no来回答的问句。 它的基本结构是：be/have /has/did等助动词（包括情态动词）＋主语＋谓语（包括表语）＋┄？回答常用简略回答。 1、谓语动词是be动词、助动词、情态动词时，只要直接把这些词置于句首，句末改成问号。 eg. there's something wrong with his bike.（改成疑问句） ______ _____ _______ wrong with his bike? 2、谓语动词是行为动词时，必须在句首加上助动词do、does（三单）、did（过去式）加上这些助动词后，句子中谓语动词必须用原形。 eg. 1)edison built a science lab himself when he was ten. （改成疑问句） ______ edison ______ a science lab himself when he was ten？ 2)those japanese like chinese food.（改成疑问句） ______ those japanese ________ chinese food? 注意：在把肯定句改成否定句或一般疑问句的时候,要注意句中是否有already、some、something、somebody等词，如果有也必须进行改变，already要改成yet，some、something、somebody等分别改成any、anything、anybody等。另外，在改成否定句的时候注意把too改成either,both改成neither,all改成none等.在改成一般疑问句的时候，常常把第一人称i、we改成第二人称you。 b.特殊疑问句：以疑问代词或疑问副词开头，提出疑问的句子。 它的基本结构是：特殊疑问词＋一般疑问句语序。但是如果疑问词在句子中作主语或作主语的定语，就用特殊疑问词＋陈述句语序。常用的疑问词有：what, who(whom), whose,which,when,where,how,why等，回答时针对问句中的代词和副词来回答，不用yes或no来回答。