肯定句变否定句

肯定——否定一、动词be的否定式动词be根据不同的人称和时态可以有am,is,are,was,were等不同形式，可用作连系动词(表示“是”、“在”等)和助动词(用于构成进行时态和被动语态等)，但不管何种情况，构成否定式时，一律在其后加not。I’mold,butyou’reyoung.→I’mnotold,butyou’renotyoung.HewasreadingandIwaswriting.→HewasnotreadingandIwasnotwriting.二、动词have的否定式动词have根据不同的人称和时态可以有have,has,had等形式，可以用作实意动词和助动词，分以下情况讨论。用作实意动词表示状态，如表示拥有、患病或用于haveto表示“必须”等，在构成否定式时可以直接在其后加not，也可根据情况在其前使用don’t,doesn’t，didn’t。Hehasacar.→Hehasn’tacar./Hedoesn’thaveacar.Hehadsomedictionaries.→Hehadn’tanydictionaries./Hedidn’thaveanydictionaries.Youhavetogowithhim.→Youhaven’ttogowithhim./Youdon’thavetogowithhim.【注】haveto构成否定式时以在其前加don’t等较为常见。用作实意动词表示动作，如表示“吃(=eat)”、“喝(=drink)”、“拿(=take)”、“收到(=receive)”、“度过(=spend)”等，构成否定式时不能直接在其后加not，而应根据情况在其前使用don’t,doesn’t,didn’t。Hehadsomecakeforbreakfast.→Hedidn’thaveanycakeforbreakfast.Wehadagoodholiday.→Wedidn’thaveagoodholiday.用作助动词构成完成时态，其否定式只能在其后加not。Ihavereadthebook.→Ihavenotreadthebook.HehadleftwhenIarrived.→Hehadn’tleftwhenIarrived.三、情态动词的否定式情态动词的否定式一般在其后加not构成。Icanfinishtheworkinanhour.→Ican’tfinishtheworkinanhour.Youmustgowithus.→Youmustn’tgowithus.Weshouldhelpthem.→Weshouldn’thelpthem.四、实意动词的否定式一般实意动词的否定式，通常应根据不同时态和人称在实意动词之前加don’t,doesn’t,didn’t等。Heworksinabank.→Hedoesn’tworkinabank.Weoftenhearfromher.→Wedon’toftenhearfromher.Imetheratthestation.→Ididn’tmeetheratthestation.注意：加上doesnot或didnot改为否定句以后，要把原句的动词改为原形动词，特别是行为动词do的第三人称单数does和过去时did，在主语后面加上doesn't或didn't以后，千万要注意把句中的does或did改为do。五、祈使句的否定结构为：don't十原形动词改为否定句时，要在句首加上don't，其它不变，即：Lookoutofthewindow．→Don'tlookoutofthewindow．当陈述句中含有something这个词时把句子改为否定句有两种方法：其一，在句中相应位置加not，再把something改成anything；其二，直接把something改为nothing即可。Thereissomethingwrongwiththeradio．把这个句子改为否定句有两种方法：其一，先把not加在is后面，再把something改为anything即：Thereisnotanythingwrongwiththeradio．其二把something直接改为nothing，即：Thereisnothingwrongwiththeradio．Ihavesomethingimportanttotellyou.把这个句子变成否定句有两种方法：其中一种方法是先把not加在have后面，再把something变成anything，即：Ihavenotanythingimportanttotellyou．第二种方法是直接把something改为nothing，即：Ihavenothingimportanttotellyou．当陈述句是一个主从复合句而主句的谓语动词是think或believe等时，把这种句子改为否定句，往往是否定think或believe等而不否定后面从句中的谓语动词，尽管意思是否定从句的谓语1．Wedomorningexerciseseveryday．We______________morningexerciseseveryday．2．Allofuscanswim．_____________________canswim．_______Joan_______I_______inClassOne．4．Thereissomethingwrongwithmybike．There______________wrongwithmybike．5．YoumaystayherebeforeIcomeback．You______________herebeforeIcomeback．6．Readthetextafterme．______________thetextafterme．7．LiLeineedssomehelpwithhisEnglish．LiLei_____________________helpwithhisEnglish．8．HesaidhewouldgotoBeijingthenextweek．He____________________________gotoBeijingthenextweek．9．Thebikehasalreadybeenmended．Thebike______________mended_______．10．Ithinkitisgoingtoraintomorrow．I____________________________goingtoraintomorrow．Key:1．don'tdo2．Noneofus3．Neither；nor；am4．isnothing5．mustn'tstay6．Don'tread7．doesn'tneedany8．didn'tsayhewould9．hasn'tbeen；yet10．don'tthinkitisalready，something