名词性从句中的辨析1.what与that引导名词性从句时有何区别请看题：—Ithink__________heneedsismorepractice.—Yes.__________heneedsmorepracticeisclear.A.what,WhatB.that,ThatC.what,ThatD.that,What此题应选C。其余三项均可能被误选。what和that都可以引导名词性从句，但有区别。如：1.what引导名词从句时，它在从句中要充当句子成分(主语、宾语等)，而that引导名词从句时，它在从句中不能充当句子成分。2.what引导名词从句时，它有词义(表示：什么；所……的[东西])；而that引导名词从句时，它没有词义。请做以下试题，注意区别what和that。如：1.________yousaidisdifferentfromthething________hetoldus.A.What,whatB.That,thatC.What,thatD.That,what2.—Ithink________hesaidistrue.—Butdon’tforgetthefact________heisacheat.A.what,whatB.that,thatC.what,thatD.that,what3.________surprisedusmostis________hespokeEnglishsowell.A.What,whatB.That,thatC.What,thatD.That,what2.注意：whether和if引导的宾语从句：whether和if引导宾语从句时可以互换使用，但下列情况用whether不用if。（1）在whetherornot结构中不可用if代替whetherIdon’tknowwhetherornothe’llcome.Iwonderwhetheritistrueornot.（2）介词后面的宾语从句用whether，不用if（3）引导主语从句和表语从句用whether不用ifWhetherwe’llgodependsontheweather.Thequestioniswhetheritisworthdoing.(4)whether可用在不定式前，if则不能.3.that引导的同位语从句与定语从句的区别：在同位语从句中：that不可以省略，不作成分;定语从句的关系代词that在定语从句作成分，作宾语时可以省略Weareinterestedinthenewsthatsomeforeignerswouldvisitourschool.Weareinterestedinthenewsthathetoldus.4.when,where引导的同位语从句与定语从句的区别：在定语从句中，when,where前有分别表示时间、地点的先行词；而在同位语从句中无此对应关系Theyhavenoideaatallwherehehasgone.(同位语从句)Goandgetyourcoat.It’sintheplacewhereyouleftit.(定语从句)5.疑问词-ever既可以引导名词性从句，也可以引导让步状语从句，而nomatter+疑问词只能引导让步状语从句NomatterwhereIgo,myheartistowardsChina.Ibelievewhateverhesays.Whateverhesays,Iwillneverbelievehim.who与whoever的区别who是“谁”的意思，表示具有疑问，who相当于anyonewho“无论谁”Whoeverleavestheroomlastoughttoturnoffthelights.Canyoutellmewhothatgentlemanis?6.注意区分it作形式主语的主语从句与强调句强调句句型Itis/was+被强调部分+that,去掉Itis/was,that，句子仍然成立。Itisnaturalthattheyshouldhavedifferentviews.主语从句Itisonlylatelythathehadafamilyhimself.强调句Whatwasitthathewanted?Idon’tknowwhatitwasthathewanted.Itwasinthehotelwherehestayedthatwediscussedtheseriousproblem7.注意it作形式主语的主语从句和as引导非限制性定语从句引导的不同Itisknowntoallthattheearthisround.Asisknowntoall,theearthi