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初中英语语法总结（从句）从句分为定语从句，状语从句和名词从句三大类。定语从句又分为限定性和非限定性从句两种，由关系代词或关系副词引导，修饰主句的某个成分。状语从句分为时间、结果、让步、原因、条件及行为方式状语从句。名词从句包括主语、宾语、表语和同位语从句及therebe句型。定语从句限定性定语从句that可代表人和事，而which只代表事；二者在从句中作主语或宾语。that作宾语时常可省略，which则不能，而且其后的“不及物动词+介词’’中的介词不能省略。which作宾语时，先行词与which之间的介词不能省。例如：1.Thefirstdollthatcouldsay“mama”wasinventedin1830．2.Thesecondhalfofhisvoyagewasbyfarthemoredangerouspart，duringwhichhesailedroundtheCapeHorn．代表a11，anything，something，nothing，much时，用that不用which，that作宾语可省略。例如：1.Icareanythingthathassomethingtodowithit．2.You'dbetterdosomethinghepreferstodotopleasehim．3.Thatisthelasttimewemeteachother．4.Icameacrossthewomanyoutoldmeaboutyesterday．who和whom引导的从句用来修饰人，分别作从句的主语和宾语。where是关系副词，用于表示地点的定语从句，而when用来表示时间。whose是关系代词，修饰名词作定语。例如:1.HenryFordisthepersonwhoismostresponsiblefordevelopingtheideaofmassproduction．2.Thekneeisthejointwherethethighbonemeetsthelargeboneofthelowerleg．3.Thenextmorning，whenshecamedowntobreakfast，Marywasbeamingwiththepleasureofanew，greatdiscovery．4.Thevisitingprofessorisafamousscientistwhosesonstudiesinmydepartment．在下列情况，限定性定语从句的关系代词可以省略：1)当关系代词在从句中作宾语或表语；或它们在从句中作介词的宾语，而该介词又在句末时；2)当先行词是that，all，only，everything，something，nothing等代词时，或先行词前有一个最高级形容词修饰时；3)当先行词前有only，any，all，first，no，last等修饰时，或先行词就是time，moment，way(anyway)，direction，distance等名词时，关系代词即可省略。例如：1.Thedelegationwehadbeenwaitingforfinallyarrived．2.Imetthewomanyoutoldmeabout．3.Shegavemeallshecouldafford．4.WithTVwecanseethingshappenalmostattheexactmomenttheyarehappening．非限定性定语从句作用:对所修饰的成分作进一步的说明，它与主句用逗号隔开;此类从句省略后其余部分仍可成立。在非限定性定语从句中，which可代表前面的整个句子；代表人时只能用who，whom，而不能用that；as也可用作关系代词。例如:1.Thetelephone，asweknow，wastheinventionofAlexanderGrahamBell．2.Livinginadamphouseforalongtimeisharmfultoone’shealth，whichisknowntoeveryone．状语从句时间状语从句:主要由when，whenever，after，before，a5，since，once，assoonas，Until，while等连词引导;结果状语从句:由so…that和such…that连接让步状语从句:由though，although，nomatter，evenif，however，whatever等词引导原因状语从句:由as，because，since和for引导条件状语从句:由if，whether，aslongas，providedthat等词引导地点状语从句:由where引导行为方式状语从句:由as引导例如：1.ThesmallgreenishflowersoftheelmtreeappearintheSpring,longbeforetheleavesgrow.2.QiongYao'snovelsusedtobesopopularthatherbooksappearedonbest-sellerlists.3.Gasballoonislesssafethanhotballoonbecauseitmaycatchfire.4.Uniformacceleration(同样的加速)occursiftherateofchangeremainsthesameoversuccessiveequalintervalsoftime．状语从句中的“主语+be”可以省略，前提是：从句主语和主句主语一致，且从句谓语“be”省略后的结构为“连词+现在分词／过去分词介词短语／形容词／名词短语”。例如：1.Whenwellfitted，glassescancorrectmostsightdefectsinhealthyeyes．2.Ifnecessary，Iwouldliketoseeyouinyouroffice.3.Althoughseriouslywounded，henevercomplained．名词从句名词从句包括主语从句、宾语从句，其中有介词与形容词的宾语从句、表语从句和同位语从句。主语从句主语从句常出现在itis+名词、形容词、分词+主语从句”的形式中例如：1.ItisreportedthatTaiwanesepopsingerMengTingweiwillholdasoloconcertinShanghaisomedaythismonth．2.Itmustbepointedoutthatyouhavefailedtomeetthedeadline．3.ItusuallyhappenedthatIwaslatebecauseoftrafficjams.主语从句还可用when，where，how，why，whether等连接副词，和who，whom，whose，what，which，whoever，whatever，whichever等连接代词来引起例如：1.Howtoarrangethemeetingisnotyourtask．2.Whosecandidatewillwintheelectionisthequestionbothpoliticalpartiesareasking．3.WhenIleaveismyowndecision.4.Whoeverwillgotothepartywon'tchangemymindofstayingathome．宾语从句宾语从句可由that，疑问代词或副词how，why和where等引出。例如：1.Topostponetheconferenceuntilnextmonthindicatedthattheywereunprepared．2.Nearlya11thestaffagreedwithwhatIsaid．3.Everyoneworriedaboutherbecausenoonewasawareofwhereshehadgone．4.Couldyouoffermoredetailsexceptthatithappenedatnight?由what，whether，how引导的宾语从句可用在介词后，而由that引导的从句只跟but，besides，except，in，save之后。例如:1.Icanhardlybelieveinwhattheyhavedone.2.Hedoesn’tknowmyphonenumberexceptthatthecitycodeis021.一些表语性的形容词，如：alarmed，amazed，annoyed，astonished，certain，confident，disappointed，glad，pleased，proud，sad，shocked，sure，surprised，worried，ect.做表语时，后面可跟由that，how等引导的宾语从句。例如：1.Iwasamazedhowhecouldpasstheexamwithoutattendingthelectures．2.HeisconfidentthathewillpasstheBand6examination．3.Shewassurprisedhowsimplehisproblemis．4.Weareallpleasedthathewillbeabletopassthefinalexamination.表语从句表语从句对主语的内容起解释和阐述的作用；若表语从句用that引起，that起连接作用，不能省略。表语从句也可用连接词how，when，where，why，what引起。由because引起的表语从句通常只用在“this／that／itisbecause”结构中。例如：1.Alogarithm(对数)iswhatisknowninalgebraexponent(代数的指数)．2.OnethingIadmiremostaboutthemisthattheyarehospitable．3.Sheworkstoohard；Thatiswhysheisexhausted．4.Imustpointoutthatwhereyouintendtobuildasuper-marketiswheretheelderlydoexerciseeveryday．同位语从句同位语从句是由两个或两个以上同一层次语言单位组成的结构，其中前项与后项所指相同，句法功能相同。同位语从句由that引导，也可由whether，how，why，where，when等来引导。例如：1.Sheignoredtheteacher'sinstructionthatshemuststudyhard．2.ThequestionwhetherornotIshouldhelphiminsuchacasetroubledmegreatly．