时间关系从句 　　定语从句

　　relativeclausesoftime关于时间的从句 　　When引导的是时间状语从句,表示在引导词的期间内进行的行为.

　　relativeclausesoftime关于时间(hopethathelps) 　　Whatarerelativeclauses? 　　Arelativeclausebeginswitharelativepronoun(who,whom,whose,which,that)andtellssomethingaboutanouninasentence. 　　Shedidnotwanttodonatemoneytoanagencythatwouldwastefunds. 　　Hefoundhisweddingring,whichhadfallentothebottomofthepool. 　　Similaradjectiveclausescanbewrittenwithwhenorwhere.Theguidelinesarethesame. 　　Springisthetimewhentherobinsreturnandthedaffodilsbloom. 　　IshoppedatBargainWorld,whereIfoundlotsofcleaningsupplies. 　　Whenarecommasneededwithrelativeclauses? 　　Commasareusedonlyiftherelativeclausedoesnotrestrictoridentifythenounitmodifies.Inthefirstsentenceabove,therelativeclauseisrestrictivebecauseitisneededtoidentifywhichtypeofagencythewomandoesnotwanttosupport.Inthesecondexample,therelativeclauseinnonrestrictive,meaningthat"weddingring"isnotfurtheridentifiedbytheclause"whichhadfallen..."Inotherwords,thatclausedoesnottelluswhatringorwhatkindofring;itonlyaddsinformationabouttheman'sweddingring. 　　Herearesomeexamplesofeachtypeofrelativeclause. 　　Restrictive(doesnothavecommas) 　　Hiscampaignpromisewastolistentothepeoplewholiveinthisdistrict.(Theclauserestricts"thepeople"tothosewholiveinonedistrict.) 　　Themachinewhichsortsthemailisbroken.(Theclausetellsuswhichmachine.) 　　Nonrestrictive(needscommas) 　　Mysister,whosearmissprained,issupposedtogivearecitalFriday.(Theclauseisnotmeanttotelluswhichsister;maybethewriterhasonlyonesister.Theclausejustaddsinformationaboutthesister.) 　　Parkville,whichisexpandingquickly,needstobuildanotherelementaryschool.(Thename"Parkville"identifiesthetown,sotheclausecannotrestrictitfurther.) 　　Commonmistakeswithrelativeclauses 　　Themostcommonmistakeswhichwritersmakeareleavingouttherelativepronounandgettingconfusedaboutwhetherarelativeclauseneedscommasornot. 　　Somesentenceswithmistakes: 　　Thethiefleftthemoneyonthecounterranawayquickly,buttheotherthieftrippedandfell. 　　ThestorysaysthatJonahwhowasastubbornmanspentsometimeinawhale'sbelly. 　　People,wholiveinthiscity,havemanychoicesfortransportation. 　　Herearethecorrectversions. 　　Thethiefwholeftthemoneyonthecounterranawayquickly,...(Ifyouseetwoverbphraseswithnoconnectingword,suchas"leftthemoneyranawayquickly,"somethingiswrongwiththesentence.Inthiscase,tofixitusearelativeclause,butdon'tforgetthepronounwho.) 　　ThestorysaysthatJonah,whowasastubbornman,spentsometimeinawhale'sbelly.(Jonahisalreadyonespecificperson,sotheclausecannotberestrictive.) 　　Peoplewholiveinthiscityhavemanychoicesfortransportation.(restrictiveclause)