英语中六大从句用法总结1.主语从句1）主语从句可直接位于主语的位置，如果从句较长，谓语又较短，可用it作形式主语，而将从句放在句末。常见的句型有：*Itisafact\apity\aquestion\goodnewsthat...*Itseems\appears\happened\hasturnedoutthat...*Itisclear\important\likely\possiblethat...*Itissaid\reported\estimated\hasbeenprovedthat...Itissaidthatcomicbookscreateaconnectionbetweenpeopleofthesamegeneration.Itseemsthattheperformanceisveryuseful.2)what引导的主语从句表示“...的东西时”，一般不用it作形式主语。Whatwelackisexperience.3)what,who,when,why,whether等词含有各自的疑问意义，但它们引导的主语从句，都用陈述语序。Howtheplanistobecarriedoutshouldbediscussedagain.IdidknowwhyIfeltlikecrying.2.宾语从句1）宾语从句可位于及物动词、介词和某些形容词后。连词that常可省略。介词后一般接疑问词引导的宾语从句。inthat(因为),exceptthat(除了),butthat(只是）已构成固定搭配，其他介词后一般不接that引导的宾语从句。*IpromisedthatIwouldchangethesituation.*AllthisisdifferentfromwhatAmericanyoungpeoplewouldsayaboutfriendship.*Heiscertainthatwatchingsomuchtelevisionisnotgoodforchildren.*Thisarticleiswell-writtenexceptthatitisabittoolong.2)宾语从句后如有宾补，要用形式宾语it来代替，而把宾语从句移至宾补之后。Hehasmadeitclearthathewouldnotchangehismind.3)在think,believe,suppose,expect等动词后的宾语从句中，如果谓语是否定的，一般将否定词移至主句谓语上，宾语从句则变成肯定形式。Hedidn'tthinkthatthemoneywaswellspent.3.表语从句表语从句出现在结构为“主语+系动词+表语从句”的句子中。表语从句除可用that,what,when,why,whether,how等引导外，还可由because,asif(though)等引导。that常可省略。如主句主语为reason,只能用that引导表语从句，不可用because.PerhapsthemostimportantthingtorememberisthatthereisnoonecommontypeoflifeinAmerica.Thereasonwhysomanypeoplediedthereisthattherewerenotenoughfoodsupplies.Itlooksasifsuccessfulinternationalculturalcommunicationwillmaketheworldsmaller.4.同位语从句同位语从句用于对前面出现的名词作进一步说明，一般用连词that引导，由于先行名词的意义不同，也可用whether,who,when,where,what,why,how等引导。常见的先行名词有fact,idea,belief,news,hope,conclusion,evidence,suggestion,order,problem,report,decision.有时由于谓语较短，将同位语从句位于谓语之后。Shefinallymadethedecisionthatshewouldjointhefashionshow.IhadnoideahowmanybooksIcouldborrowatatime.Thenewscamethattheirteamhadwonthechampionship.5.定语从句定语从句所修饰的先行词可以是名词或代词，也可以是一个句子。定语从句通常位于先行词之后，由关系代词或关系副词引导。*限制性定语从句限制性定语从句修饰先行词，对先行词起修饰作用，紧接先行词之后，无逗号，若省去，原句意思