2025人教版高考英語定語從句練習(xí)題50題帶答案單選題1.I'llneverforgetthedays________wespenttogetherinthecountryside.A.whenB.whereC.whichD.inwhich答案：C。本題考查定語從句。先行詞是thedays，在定語從句“wespenttogetherinthecountryside”中，spent后面缺少賓語，所以要用關(guān)系代詞which或that來引導(dǎo)，這里which符合要求。A選項(xiàng)when在定語從句中作時(shí)間狀語；B選項(xiàng)where在定語從句中作地點(diǎn)狀語；D選項(xiàng)inwhich相當(dāng)于when，作時(shí)間狀語，均不符合本題要求。2.Thehouse________windowsfacesouthisourreading-room.A.whoseB.whichC.itsD.ofwhich答案：A。先行詞是thehouse，在定語從句“windowsfacesouth”中，windows和thehouse是所屬關(guān)系，即“房子的窗戶”，所以要用關(guān)系代詞whose來引導(dǎo)定語從句，表示所屬關(guān)系。B選項(xiàng)which不能表示所屬關(guān)系；C選項(xiàng)its不能引導(dǎo)定語從句；D選項(xiàng)ofwhich表示所屬關(guān)系時(shí)，結(jié)構(gòu)一般是“the+名詞+ofwhich”，如“thewindowsofwhich”，而本題中沒有這種結(jié)構(gòu)，所以也不正確。3.Thisistheverybook________Iamlookingfor.A.thatB.whichC.whoD.as答案：A。先行詞book前有thevery修飾，當(dāng)先行詞被theonly,thevery,thelast等詞修飾時(shí)，定語從句要用關(guān)系代詞that引導(dǎo)，而不用which。C選項(xiàng)who指人；D選項(xiàng)as引導(dǎo)定語從句時(shí)，通常用于一些固定結(jié)構(gòu)，如“such...as”“thesame...as”等，本題不符合這些結(jié)構(gòu)，所以本題選A。4.Theman________youmetjustnowismyoldfriend.A.whereB.whichC.whomD.when答案：C。先行詞是theman，指人，在定語從句“youmetjustnow”中，met是及物動(dòng)詞，后面缺少賓語，所以要用關(guān)系代詞whom或who來引導(dǎo)，這里whom符合要求。A選項(xiàng)where在定語從句中作地點(diǎn)狀語；B選項(xiàng)which指物；D選項(xiàng)when在定語從句中作時(shí)間狀語，均不符合本題要求。5.Thefactory________hisfatherworksisinthewestofthecity.A.thatB.whichC.whereD.when答案：C。先行詞是thefactory，在定語從句“hisfatherworks”中，work是不及物動(dòng)詞，從句不缺少賓語，而需要一個(gè)表示地點(diǎn)的狀語，所以要用關(guān)系副詞where來引導(dǎo)定語從句。A選項(xiàng)that和B選項(xiàng)which在定語從句中一般作主語或賓語；D選項(xiàng)when在定語從句中作時(shí)間狀語，均不符合本題要求。6.Istillremembertheday________IfirstcametoBeijing.A.thatB.whichC.whenD.where答案：C。先行詞是theday，在定語從句“IfirstcametoBeijing”中，從句不缺少主語或賓語，而是缺少時(shí)間狀語，所以要用關(guān)系副詞when來引導(dǎo)定語從句。A選項(xiàng)that和B選項(xiàng)which在定語從句中一般作主語或賓語；D選項(xiàng)where在定語從句中作地點(diǎn)狀語，均不符合本題要求。7.Thereason________hewaslateisthathemissedtheearlybus.A.whyB.whichC.thatD.when答案：A。先行詞是thereason，在定語從句“hewaslate”中，從句不缺少主語或賓語，而是缺少原因狀語，所以要用關(guān)系副詞why來引導(dǎo)定語從句。B選項(xiàng)which在定語從句中作主語或賓語；C選項(xiàng)that引導(dǎo)定語從句時(shí)，先行詞一般不是thereason；D選項(xiàng)when在定語從句中作時(shí)間狀語，均不符合本題要求。8.Heistheonlyoneofthestudents________thetruth.A.whoknowB.whoknowsC.thatknowD.whichknows答案：B。先行詞是theonlyoneofthestudents，強(qiáng)調(diào)的是“唯一的一個(gè)學(xué)生”，關(guān)系代詞在定語從句中作主語，謂語動(dòng)詞要和先行詞theonlyone保持一致，用第三人稱單數(shù)形式。關(guān)系代詞指人，可用who或that引導(dǎo)定語從句，所以用whoknows。A選項(xiàng)know形式錯(cuò)誤；C選項(xiàng)know形式錯(cuò)誤；D選項(xiàng)which指物，不符合本題要求。9.Thegirl________anEnglishsonginthenextroomisTom'ssister.A.whoissingingB.issingingC.sangD.wassinging答案：A。本題考查定語從句。先行詞是thegirl，指人，在定語從句中作主語，且從句表示“正在唱英文歌”，要用現(xiàn)在進(jìn)行時(shí)態(tài)，所以用whoissinging來引導(dǎo)定語從句。B選項(xiàng)缺少引導(dǎo)詞；C選項(xiàng)sang是過去式，不符合語境；D選項(xiàng)wassinging是過去進(jìn)行時(shí)，不符合語境。10.Thefilm________wesawlastnightwaswonderful.A.thatB.whatC.whoseD.who答案：A。先行詞是thefilm，指物，在定語從句“wesawlastnight”中作saw的賓語，可用關(guān)系代詞that或which引導(dǎo)定語從句，這里that符合要求。B選項(xiàng)what不能引導(dǎo)定語從句；C選項(xiàng)whose表示所屬關(guān)系，不符合本題要求；D選項(xiàng)who指人，不符合本題要求。11.Theplace________interestedmemostwastheChildren'sPalace.A.whichB.whereC.whatD.inwhich答案：A。先行詞是theplace，指物，在定語從句“interestedmemost”中作主語，可用關(guān)系代詞that或which引導(dǎo)定語從句，這里which符合要求。B選項(xiàng)where在定語從句中作地點(diǎn)狀語；C選項(xiàng)what不能引導(dǎo)定語從句；D選項(xiàng)inwhich相當(dāng)于where，作地點(diǎn)狀語，均不符合本題要求。12.Doyouknowtheman________?A.whomIspokeB.towhospokeC.IspoketoD.thatIspoke答案：C。先行詞是theman，指人，在定語從句中作to的賓語，關(guān)系代詞可以省略。speakto是固定搭配，A選項(xiàng)whomIspoke缺少to；B選項(xiàng)towho形式錯(cuò)誤，應(yīng)該是towhom；D選項(xiàng)thatIspoke缺少to，所以本題選C。13.Thisisthehotel________lastmonth.A.whichtheystayedB.atthattheystayedC.wheretheystayedatD.wheretheystayed答案：D。先行詞是thehotel，在定語從句“theystayed”中，stay是不及物動(dòng)詞，從句不缺少賓語，需要一個(gè)表示地點(diǎn)的狀語，用關(guān)系副詞where引導(dǎo)定語從句，where相當(dāng)于atwhich。A選項(xiàng)whichtheystayed缺少介詞；B選項(xiàng)atthat形式錯(cuò)誤，介詞后不能用that；C選項(xiàng)wheretheystayedat中，where已經(jīng)表示地點(diǎn)，at多余，所以本題選D。14.Thepen________heiswritingismine.A.withwhichB.inwhichC.onwhichD.bywhich答案：A。先行詞是thepen，在定語從句“heiswriting”中，writewithapen是固定搭配，表示“用鋼筆寫”，所以用withwhich引導(dǎo)定語從句。B選項(xiàng)inwhich一般表示“在……里面”；C選項(xiàng)onwhich一般表示“在……上面”；D選項(xiàng)bywhich一般表示“通過……方式”，均不符合本題要求。15.Thereisnodifficulty________can'tbeovercomeintheworld.A.thatB.whichC.whoD.what答案：A。先行詞是difficulty，指物，且前面有no修飾，當(dāng)先行詞被no,all,few等詞修飾時(shí)，定語從句要用關(guān)系代詞that引導(dǎo)，而不用which。C選項(xiàng)who指人；D選項(xiàng)what不能引導(dǎo)定語從句，所以本題選A。16.Thesecondbook________IwanttoreadisBusinessattheSpeedofThought.A.whichB.whatC.thatD.as答案：C。先行詞book前有序數(shù)詞thesecond修飾，當(dāng)先行詞被序數(shù)詞修飾時(shí)，定語從句要用關(guān)系代詞that引導(dǎo)，而不用which。B選項(xiàng)what不能引導(dǎo)定語從句；D選項(xiàng)as引導(dǎo)定語從句時(shí)，通常用于一些固定結(jié)構(gòu)，如“such...as”“thesame...as”等，本題不符合這些結(jié)構(gòu)，所以本題選C。17.Theman________hasalotofmoneyisourboss.A.whoB.whomC.whoseD.which答案：A。先行詞是theman，指人，在定語從句中作主語，要用關(guān)系代詞who引導(dǎo)定語從句。B選項(xiàng)whom在定語從句中作賓語；C選項(xiàng)whose表示所屬關(guān)系；D選項(xiàng)which指物，均不符合本題要求。18.Thebuilding________roofwecanseefromhereisahotel.A.whoseB.whichC.thatD.ofwhich答案：A。先行詞是thebuilding，在定語從句“roofwecanseefromhere”中，roof和thebuilding是所屬關(guān)系，即“建筑物的屋頂”，所以用關(guān)系代詞whose來引導(dǎo)定語從句。B選項(xiàng)which不能表示所屬關(guān)系；C選項(xiàng)that不能表示所屬關(guān)系；D選項(xiàng)ofwhich表示所屬關(guān)系時(shí)，結(jié)構(gòu)一般是“the+名詞+ofwhich”，如“theroofofwhich”，本題用whose更合適，所以本題選A。19.Ilikethestories________havehappyendings.A.whoB.thatC.whereD.when答案：B。先行詞是thestories，指物，在定語從句“havehappyendings”中作主語，可用關(guān)系代詞that或which引導(dǎo)定語從句，這里that符合要求。A選項(xiàng)who指人；C選項(xiàng)where在定語從句中作地點(diǎn)狀語；D選項(xiàng)when在定語從句中作時(shí)間狀語，均不符合本題要求。20.Thewoman________youtalkedtojustnowisournewteacher.A.whoseB.whichC.whomD.when答案：C。先行詞是thewoman，指人，在定語從句“youtalkedtojustnow”中，作to的賓語，要用關(guān)系代詞whom或who來引導(dǎo)，這里whom符合要求。A選項(xiàng)whose表示所屬關(guān)系；B選項(xiàng)which指物；D選項(xiàng)when在定語從句中作時(shí)間狀語，均不符合本題要求。多選題1.Whichofthefollowingsentencesusecorrectrelativeclauses?A.TheboywhoiswearingaredT-shirtismybrother.B.ThebookwhichIboughtyesterdayisveryinteresting.C.Theplacewherewevisitedlastweekisreallybeautiful.D.Thereasonwhyhewasabsentisamystery.答案：ABD。A選項(xiàng)中，先行詞是theboy，指人，在定語從句“iswearingaredT-shirt”中作主語，用who引導(dǎo)定語從句正確；B選項(xiàng)中，先行詞是thebook，指物，在定語從句“Iboughtyesterday”中作bought的賓語，用which引導(dǎo)定語從句正確；C選項(xiàng)中，先行詞是theplace，在定語從句“wevisitedlastweek”中，visited是及物動(dòng)詞，從句缺少賓語，應(yīng)該用which或that引導(dǎo)，而where在定語從句中作地點(diǎn)狀語，所以該選項(xiàng)錯(cuò)誤；D選項(xiàng)中，先行詞是thereason，在定語從句“hewasabsent”中，缺少原因狀語，用why引導(dǎo)定語從句正確。2.Choosethecorrectrelativepronounsoradverbsforthefollowingsentences.A.Thehouseinthathelivesisveryold.B.ThegirlwhomImetatthepartyisverykind.C.Thedaywhenwewenttothebeachwassunny.D.Themanwhosecarwasstolenisveryangry.答案：BCD。A選項(xiàng)中，介詞in后不能用that，應(yīng)該用which，所以該選項(xiàng)錯(cuò)誤；B選項(xiàng)中，先行詞是thegirl，在定語從句“Imetattheparty”中作met的賓語，用whom引導(dǎo)定語從句正確；C選項(xiàng)中，先行詞是theday，在定語從句“wewenttothebeach”中，缺少時(shí)間狀語，用when引導(dǎo)定語從句正確；D選項(xiàng)中，先行詞是theman，在定語從句“carwasstolen”中，car和theman是所屬關(guān)系，用whose引導(dǎo)定語從句正確。3.Whichsentencescanberewrittenusingrelativeclauses?A.Isawaman.Themanwascarryingabigbox.B.Shehasabook.Thebookisverythick.C.Wewenttoapark.Weplayedfootballthere.D.Hehasadog.Thedog'snameisLucky.答案：ABCD。A選項(xiàng)可改寫為“Isawamanwho/thatwascarryingabigbox”；B選項(xiàng)可改寫為“Shehasabookwhich/thatisverythick”；C選項(xiàng)可改寫為“Wewenttoaparkwhereweplayedfootball”；D選項(xiàng)可改寫為“HehasadogwhosenameisLucky”。4.Thefollowingsentencescontainrelativeclauses.Whichonesarecorrect?A.Thestudentswhostudyhardwillgetgoodgrades.B.Thetreewhichleavesaregreenisverytall.C.Themoviethatwewatchedlastnightwasexciting.D.ThetownwhereIwasbornisverysmall.答案：ACD。A選項(xiàng)中，先行詞是thestudents，指人，在定語從句“studyhard”中作主語，用who引導(dǎo)定語從句正確；B選項(xiàng)中，應(yīng)該用whose表示所屬關(guān)系，即“thetreewhoseleavesaregreen”，而不是which，所以該選項(xiàng)錯(cuò)誤；C選項(xiàng)中，先行詞是themovie，指物，在定語從句“wewatchedlastnight”中作watched的賓語，用that引導(dǎo)定語從句正確；D選項(xiàng)中，先行詞是thetown，在定語從句“Iwasborn”中，缺少地點(diǎn)狀語，用where引導(dǎo)定語從句正確。5.Selecttheproperrelativeelementsfortheblanks.A.Theperson________youshouldtalktoisMr.Smith.(whom/that)B.Thecity________IwanttovisitisParis.(which/where)C.Thetime________wewillmeetis3p.m.(when/that)D.Thebuilding________doorsareallclosedisalibrary.(whose/ofwhich)答案：ACD。A選項(xiàng)中，先行詞是theperson，指人，在定語從句“youshouldtalkto”中作to的賓語，可用whom或that引導(dǎo)定語從句，所以whom/that正確；B選項(xiàng)中，先行詞是thecity，在定語從句“Iwanttovisit”中作visit的賓語，應(yīng)該用which或that引導(dǎo)定語從句，而where在定語從句中作地點(diǎn)狀語，所以該選項(xiàng)錯(cuò)誤；C選項(xiàng)中，先行詞是thetime，在定語從句“wewillmeet”中，缺少時(shí)間狀語，可用when或that引導(dǎo)定語從句，所以when/that正確；D選項(xiàng)中，先行詞是thebuilding，在定語從句“doorsareallclosed”中，doors和thebuilding是所屬關(guān)系，可用whose或ofwhich引導(dǎo)定語從句，所以whose/ofwhich正確。6.Whichofthefollowingarecorrectrelative-clauseusages?A.Thecatthatcaughtthemouseisverysmart.B.Theladywhomhersonisadoctorisveryproud.C.TheschoolwhereIstudiedforthreeyearsisverybeautiful.D.Thereasonwhichhegaveisnotbelievable.答案：ACD。A選項(xiàng)中，先行詞是thecat，指物，在定語從句“caughtthemouse”中作主語，用that引導(dǎo)定語從句正確；B選項(xiàng)中，whom不能和her同時(shí)使用，應(yīng)改為whose，所以該選項(xiàng)錯(cuò)誤；C選項(xiàng)中，先行詞是theschool，在定語從句“Istudiedforthreeyears”中，缺少地點(diǎn)狀語，用where引導(dǎo)定語從句正確；D選項(xiàng)中，先行詞是thereason，在定語從句“hegave”中作gave的賓語，用which引導(dǎo)定語從句正確。7.Choosethecorrectsentenceswithrelativeclauses.A.Theboywho'sfatherisateacherisveryhard-working.B.ThebookwhichI'mreadingnowisaboutscience.C.Thevillagewheretherearemanytreesisveryquiet.D.Themanthathelpedmeyesterdayisavolunteer.答案：BCD。A選項(xiàng)中，who's是whois的縮寫，這里應(yīng)該用whose表示所屬關(guān)系，所以該選項(xiàng)錯(cuò)誤；B選項(xiàng)中，先行詞是thebook，指物，在定語從句“I'mreadingnow”中作reading的賓語，用which引導(dǎo)定語從句正確；C選項(xiàng)中，先行詞是thevillage，在定語從句“therearemanytrees”中，缺少地點(diǎn)狀語，用where引導(dǎo)定語從句正確；D選項(xiàng)中，先行詞是theman，指人，在定語從句“helpedmeyesterday”中作主語，用that引導(dǎo)定語從句正確。8.Whichrelative-clausesentencesareaccurate?A.Thehousewhichstandsonthehillisveryold.B.Thegirlwhosehairislongismyclassmate.C.Thedaywhenwehadapartywasunforgettable.D.Theshopthatsellsclothesisnearmyhome.答案：ABCD。A選項(xiàng)中，先行詞是thehouse，指物，在定語從句“standsonthehill”中作主語，用which引導(dǎo)定語從句正確；B選項(xiàng)中，先行詞是thegirl，在定語從句“hairislong”中，hair和thegirl是所屬關(guān)系，用whose引導(dǎo)定語從句正確；C選項(xiàng)中，先行詞是theday，在定語從句“wehadaparty”中，缺少時(shí)間狀語，用when引導(dǎo)定語從句正確；D選項(xiàng)中，先行詞是theshop，指物，在定語從句“sellsclothes”中作主語，用that引導(dǎo)定語從句正確。9.Selecttherightrelative-clauseforms.A.ThemantowhoIlentmymoneyismyneighbor.B.Theflowerwhichcolorisredisverybeautiful.C.Themuseumwherewesawmanypaintingsisveryfamous.D.Thestudentthatansweredthequestioncorrectlyispraised.答案：CD。A選項(xiàng)中，to后應(yīng)該用whom，而不是who，所以該選項(xiàng)錯(cuò)誤；B選項(xiàng)中，應(yīng)該用whose表示所屬關(guān)系，即“theflowerwhosecolorisred”，所以該選項(xiàng)錯(cuò)誤；C選項(xiàng)中，先行詞是themuseum，在定語從句“wesawmanypaintings”中，缺少地點(diǎn)狀語，用where引導(dǎo)定語從句正確；D選項(xiàng)中，先行詞是thestudent，指人，在定語從句“answeredthequestioncorrectly”中作主語，用that引導(dǎo)定語從句正確。10.Whichofthesesentencesuserelativeclausesappropriately?A.Thecarthathasaflattireneedstoberepaired.B.ThewomanwhomIsawinthesupermarketismyaunt.C.Theparkwhereweoftengoforawalkisverylarge.D.Thebookwhosecoverisblueismine.答案：ABCD。A選項(xiàng)中，先行詞是thecar，指物，在定語從句“hasaflattire”中作主語，用that引導(dǎo)定語從句正確；B選項(xiàng)中，先行詞是thewoman，指人，在定語從句“Isawinthesupermarket”中作saw的賓語，用whom引導(dǎo)定語從句正確；C選項(xiàng)中，先行詞是thepark，在定語從句“weoftengoforawalk”中，缺少地點(diǎn)狀語，用where引導(dǎo)定語從句正確；D選項(xiàng)中，先行詞是thebook，在定語從句“coverisblue”中，cover和thebook是所屬關(guān)系，用whose引導(dǎo)定語從句正確。填空題1.Theman_________yousawjustnowismyuncle.答案：whom/who/that。先行詞是theman，指人，在定語從句“yousawjustnow”中作saw的賓語，可用關(guān)系代詞whom、who或that引導(dǎo)定語從句。2.Thehouse_________windowsfacesouthisverywarminwinter.答案：whose。先行詞是thehouse，在定語從句“windowsfacesouth”中，windows和thehouse是所屬關(guān)系，用關(guān)系代詞whose引導(dǎo)定語從句。3.I'llneverforgettheday_________IjoinedtheParty.答案：when。先行詞是theday，在定語從句“IjoinedtheParty”中，缺少時(shí)間狀語，用關(guān)系副詞when引導(dǎo)定語從句。4.Thefactory_________heworksisalargeone.答案：where。先行詞是thefactory，在定語從句“heworks”中，缺少地點(diǎn)狀語，用關(guān)系副詞where引導(dǎo)定語從句。5.Thereason_________hewaslateisthathemissedthebus.答案：why。先行詞是thereason，在定語從句“hewaslate”中，缺少原因狀語，用關(guān)系副詞why引導(dǎo)定語從句。6.Thebook_________I'mreadingisveryinteresting.答案：which/that。先行詞是thebook，指物，在定語從句“I'mreading”中作reading的賓語，可用關(guān)系代詞which或that引導(dǎo)定語從句。7.Thegirl_________issingingonthestageismysister.答案：who/that。先行詞是thegirl，指人，在定語從句“issingingonthestage”中作主語，可用關(guān)系代詞who或that引導(dǎo)定語從句。8.Thecity_________wevisitedlastyearisverybeautiful.答案：which/that。先行詞是thecity，在定語從句“wevisitedlastyear”中作visited的賓語，可用關(guān)系代詞which或that引導(dǎo)定語從句。9.Thetree_________standsinfrontofmyhouseisverytall.答案：which/that。先行詞是thetree，指物，在定語從句“standsinfrontofmyhouse”中作主語，可用關(guān)系代詞which或that引導(dǎo)定語從句。10.Theperson_________youtalkedtoatthepartyismyfriend.答案：whom/who/that。先行詞是theperson，指人，在定語從句“youtalkedtoattheparty”中作to的賓語，可用關(guān)系代詞whom、who或that引導(dǎo)定語從句。改錯(cuò)題1.Thisisthefactorywherewevisitedlastweek.答案：將where改為which/that。先行詞是thefactory，在定語從句“wevisitedlastweek”中作visited的賓語，應(yīng)該用關(guān)系代詞which或that引導(dǎo)定語從句，而where在定語從句中作地點(diǎn)狀語，所以要將where改為which/that。2.ThemanwhoIgavethebookismyteacher.答案：在who前加to或把who改為whom。“givesth.tosb.”是固定搭配，原句中缺少to，也可以把who改為whom，因?yàn)閣hom可以作to的賓語。3.Thereasonwhichhewaslateisthathemissedthetrain.答案：將which改為why。先行詞是thereason，在定語從句“hewaslate”中，缺少原因狀語，要用關(guān)系副詞why引導(dǎo)定語從句，而which在定語從句中一般作主語或賓語，所以要將which改為why。4.Thehouseitswindowsfacesouthisverybright.答案：將its改為whose。先行詞是thehouse，在定語從句“windowsfacesouth”中，windows和thehouse是所屬關(guān)系，要用關(guān)系代詞whose引導(dǎo)定語從句，而its不能引導(dǎo)定語從句，所以要將its改為whose。5.ThegirlwhoImetheratthepartyisverylovely.答案：去掉her。先行詞是thegirl，在定語從句“Imet”中作met的賓語，關(guān)系代詞who/whom/that可以省略，her多余，所以要去掉her。6.ThedaywhenwehadagoodtimewasSunday.答案：此句正確。先行詞是theday，在定語從句“wehadagoodtime”中，缺少時(shí)間狀語，用關(guān)系副詞when引導(dǎo)定語從句，句子結(jié)構(gòu)和用法正確。7.Thepenwiththathewritesisverynice.答案：將that改為which。介詞with后不能用that，應(yīng)該用which引導(dǎo)定語從句，所以要將that改為which。8.Themanwhichhelpedmeisapoliceman.答案：將which改為who/that。先行詞是theman，指人，在定語從句“helpedme”中作主語，要用關(guān)系代詞who或that引導(dǎo)定語從句，而which指物，所以要將which改為who/that。9.ThebookwhatIboughtyesterdayisveryuseful.答案：將what改為which/that。what不能引導(dǎo)定語從句，先行詞是thebook，指物，在定語從句“Iboughtyesterday”中作bought的賓語，要用關(guān)系代詞which或that引導(dǎo)定語從句，所以要將what改為which/that。10.Theplacewherewetookmanyphotosisverybeautiful.答案：此句正確。先行詞是theplace，在定語從句“wetookmanyphotos”中，缺少地點(diǎn)狀語，用關(guān)系副詞where引導(dǎo)定語從句，句子結(jié)構(gòu)和用法正