許多同學(xué)在學(xué)習(xí)復(fù)合句和特殊句式時(shí)，都會(huì)為“that”和“what”的選擇而頭疼， 感覺這兩個(gè)連接性詞語辨別起來“有點(diǎn)亂”。下面奉上區(qū)分that和what的方法，快來看看吧！
做一做下面幾個(gè)題，看看你能否把他們分清：
1.A modern city has been set up in ____ was a wasteland ten years ago.
A. what B. which C. that D. where
2.Because of my poor memory, all ____ you told me has been forgotten.
A. that B. which C. what D. as
3.With his work completed, the businessman stepped back to his seat, feeling pleased ____ he was a man of action.
A. which B. that C. what D. whether
4.It is what you do rather than what you say _______ matters.
A. that B. what C. which D. this
5.His plan was such a good one _________ we all agreed to accept it.
A. so B. and C. that D. as
上面5個(gè)題中的前四個(gè)題，在選項(xiàng)中都同時(shí)出現(xiàn)了what和that，如何選擇呢？
第1題為答案A。考查名詞從句連接代詞what的運(yùn)用。“十年前是一片荒地的地方建起了一座現(xiàn)代化的城市”。作介詞in的賓語不能用that，因?yàn)槊~從句中that不做任何成分；連接代詞what引導(dǎo)一個(gè)賓語從句，“是一個(gè)什么樣的地方”；
第2題為答案A。考查定詞從句關(guān)系代詞that的運(yùn)用，“因?yàn)橛洃洸缓茫愀嬖V我的，我都給忘了”。句中先行詞為“all”，that為關(guān)系代詞，意指all，在從句中做賓語；
第3題答案為B?？疾槊~從句從屬連詞that的運(yùn)用?！啊艿靡庾约菏莻€(gè)干事的人?！标愂隽艘粋€(gè)事實(shí)，故選擇從屬連詞that
第4題為答案A?？疾閺?qiáng)調(diào)句結(jié)構(gòu)中的that。“It is （was） + 所強(qiáng)調(diào)的成分 + that （who） + 其他成分?！?BR> 第5題為答案C?？疾榻Y(jié)果狀語從句中的從屬連詞that?！八挠?jì)劃非常好，我們都同意接受。”
從上面的分析中，我們不難看出，“that”一詞非常活躍，在定語從句、名詞從句、狀語從句和強(qiáng)調(diào)句中都有使用；而命題設(shè)項(xiàng)時(shí)，“what”又常常用來作為干擾，因此，要想辨清“that” 和“what”這兩個(gè)詞，突破復(fù)合句式的這個(gè)難點(diǎn)，就要注意：
一、定語從句的關(guān)系代詞中沒有what，因此要牢記what不會(huì)引導(dǎo)定語從句。
例如：
1.The thought of going back home was kept him happy while he was working abroad.
A.that B.all that C.all what D.which
答案為B。這里的all是先行詞，而that是關(guān)系代詞，在從句中做主語。許多同學(xué)將此題誤選成了C。需要注意的是，C選項(xiàng)前面要是去掉all，則變成了what引導(dǎo)的名詞從句，則就是對的了。
2.You can only be sure of_____ you have at present; you cannot be sure of something ___ you might get in the future. [2007 安徽卷]
A. that; what B. what; /
C. which; that D. /; that
答案為B。前一個(gè)空為名詞從句連接代詞what，（從句做of的賓語，what又為get的賓語），后一個(gè)空為定語從句（先行詞為something，關(guān)系代詞做get的賓語，關(guān)系代詞省略）。
二、名詞從句中同時(shí)存在that和what這兩個(gè)連接性詞語，可以從其語法地位和意思上來辨別。
that 引導(dǎo)名詞性從句時(shí)，沒有任何含義和語法作用，只是提示引導(dǎo)了名詞從句；而what引導(dǎo)名詞性從句時(shí)，在主從句中都要充當(dāng)一定的句子成分，what的意思是“什么…”
例如：
1.The mountain is no longer ____ it used to be.
A. which B. that C. what D. as
答案C ?！吧讲皇且郧澳莻€(gè)樣子了”。以前“什么樣”，對應(yīng)了what。
2.There is much chance ____ Bill will recover from his injury in time for the race.
A. that B. which C. until D. if
答案A。that引導(dǎo)的名詞從句陳述事實(shí)，說的即是前面的chance，為同位語從句。
三、定語從句與同位語從句中that的區(qū)別，主要看that在從句中有沒有語法作用。
定語從句中的關(guān)系代詞that在句中做賓語或主語，有時(shí)可以與 which 互換。同位語從句中的連詞that只起連接作用，在從句中不擔(dān)當(dāng)任何句子成分；而如果句子是同位語從句，就應(yīng)用連詞that而不能用which。同位語從句一般放在表具體含義的名詞如：fact、suggestion、truth、possibility、idea等后面，解釋名詞的含義或內(nèi)容，而定語從句只是對先行詞的限定和修飾。
例如：
The football star Henry expressed the hope that he would come to visit China again in 2008.
同位語從句，從句就是hope的內(nèi)容；
The hope the football star Henry expressed is that he would come to visit China again in 2008.
定語從句，從句修飾hope，是“表達(dá)的”愿望。
再如：
1.…It's thirty years since we last met.
…But I still remember the story, believe it or not, ____ we got lost on a rainy night.
A. which B. that C. what D. when
答案為B。同位語從句，解釋story。
2.I still remember the big names in the stories ______ my mother told me when I was young.
A. when B. that C. what D. where
答案為B。定語從句，意指stories，做told的賓語。
名詞性從句中that和what的用法區(qū)別
一。that 引導(dǎo)的名詞性從句
首先，連接代詞that除引導(dǎo)第一個(gè)賓語從句時(shí)可以省略外，引導(dǎo)其他各類名詞性從句皆不能省略。例如：
① It is required in the regulations that you should not tell other people the password of your e-mail account.
② ---- Don't you think it necessary that he go home at once?
---- but the problem is that there is no car.
③ There is much chance that Bill will recover from his injury in time for the race.
④ Our English teacher told us （that） we all did very well in the examination and that ten of us got full mark.
以上四個(gè)句子中，that 分別引導(dǎo)主語從句，表語從句，同位語從句和賓語從句，除在第四個(gè)例句中第一個(gè)that 可以省略外，其他的that 均不可省略。
其次，在引導(dǎo)名詞性從句時(shí)，that不作句子中的任何成分。例如：
① Nobody believed his reason for being absent from the class that he had to meet his uncle at the airport.
該句中，that引導(dǎo)同位語從句，但在句中不作任何成分。
② It is our belief that improvements in health care will lead to a stronger, more prosperous economy.
該句中，it 是形式主語，that引導(dǎo)的主語從句才是整個(gè)句子的真正主語，that在句中不作任何成分。
最后，在引導(dǎo)名詞性從句時(shí)，that沒有任何詞匯意義。
① A warm thought suddenly came to me that I might use the pocket money to buy some flowers for my mother's birthday.
② Danby left word with my secretary that he would call again in the afternoon.
在以上兩個(gè)考例中，that僅起引導(dǎo)同位語從句的作用，沒有任何詞匯意義。
綜上所述，that 在引導(dǎo)名詞性從句時(shí)具有三大特點(diǎn)：不可省略，不作成分，沒有詞義。
二。 what引導(dǎo)的名詞性從句
首先，what 引導(dǎo)名詞性從句時(shí)，what 在句中不省略。
這一用法與that引導(dǎo)名詞性從句時(shí)的用法不盡相同。
① He spoke proudly of his part in the game, without mentioning what his teammates had done.
what 在該句中引導(dǎo)賓語從句，what 不可省略。
② Great changes have taken place in that school. It is no longer what it was 20 years ago, when it was so poorly equipped.
what在該句中引導(dǎo)表語從句，但在句中不可省略。
其次，what 引導(dǎo)名詞性從句時(shí)，具有詞匯意義。
這是what 與that 引導(dǎo)名詞性從句的重要區(qū)別之一，What 一般指“----的東西/事情/人/時(shí)間/地點(diǎn)等”。例如：
① Do you have any idea what is actually going on in the classroom?
what在該句中引導(dǎo)同位語從句并作這個(gè)同位語從句的主語，詞義為“----的東西、事情”，整個(gè)句子的漢語意思是“你知道教室里到底發(fā)生了什么事”。
② It is what you do rather than what you say that matters.
這是一個(gè)強(qiáng)調(diào)句型，被強(qiáng)調(diào)的部分是由what引導(dǎo)的兩個(gè)主語從句，what在句中的詞義為“----的東西、事情”，整個(gè)句子的漢語意思是“關(guān)鍵要看你做什么而不是說什么”。
最后，what 引導(dǎo)名詞性從句時(shí)不僅只起引導(dǎo)作用，同時(shí)還要作句中的某個(gè)句法成分。
這一點(diǎn)是what 在引導(dǎo)名詞性從句時(shí)與that 用法區(qū)別的關(guān)鍵所在。
① I just wonder_________ that makes him so excited.
A. why it does B. what he does C. how it is D. what it is
這一題的正確答案是D,是一個(gè)強(qiáng)調(diào)句型作賓語的典型考例，被強(qiáng)調(diào)的成分what 在句中不僅只起引導(dǎo)賓語從句的作用，同時(shí)在賓語從句中作makes 的主語。
② A modern city has been set up in what was a wasteland ten years ago.
在這個(gè)句子中，what 引導(dǎo)的從句作了介詞in 的賓語，同時(shí)what 又在賓語從句中充當(dāng)主語，意思是“……的地方”。值得注意的是，在引導(dǎo)名詞性從句時(shí)，that 引導(dǎo)的句子一般不作介詞的賓語，相反，由what 引導(dǎo)的句子作介詞賓語的情況顯得更為常見。例如：
③ The other day, my brother drove his car down the street at what I thought was a dangerous speed.
本題中，介詞at后面用了what引導(dǎo)的賓語從句，what在賓語從句中作主語，而that不可以這樣使用。
綜上所述，what 在引導(dǎo)名詞性從句時(shí)具有三大特點(diǎn)：不可省略，作成分，有詞義。
That 與what 所引導(dǎo)的句子是高考的熱點(diǎn)，為使同學(xué)們較好地掌握它們的用法與區(qū)別，現(xiàn)將其用法要點(diǎn)歸納如下
一。主語從句
連詞that 引導(dǎo)主語從句位于句首時(shí)沒有意義，在從句中也不作句子成分，不能省略。但多數(shù)情況下還是用it 作形式主語，將that 從句后置。而what引導(dǎo)主語從句相當(dāng)于the thing that,表示“所…的”，在句中作句子成分，不能省略。
Eg ⑴ That fashion differs from country to country may reflect the cultural differences from one aspect.
（2） It is important that students should master a foreign language .
（3）What the president remarked at the conference made the world shock .
注意在含有主語從句的復(fù)合句是疑問句時(shí)，that從句不可以提前。
Is it possible that he will win the game ? （正）
Is that he will win the game possible ? （誤）
二。賓語從句
主句的謂語動(dòng)詞如果用that引導(dǎo)賓語從句，that只是引導(dǎo)詞，不在句中作任何成分，有時(shí)可以省略；而what 引導(dǎo)賓語從句，在句子作相應(yīng)的句子成分，相當(dāng)于the thing that.表示“所…的”，不能省略。同時(shí)要注意與強(qiáng)調(diào)句型where,when引導(dǎo)的狀語從句等的區(qū)別。
Eg It is at the factory that he worked for 20 years.（強(qiáng)調(diào)句型）
It is the factory where he worked for 20 years.（定語從句）
It was at three o′clock that he got home. （強(qiáng)調(diào)句型）
It was three o′clock when he got home. （狀語從句）
注意形容詞anxious,certain, glad, afraid, proud, surprised, sorry, pleased等常跟that 引導(dǎo)從句作賓語。
Eg I am certain that our team will win the game.
We are sorry that he didn't pass the exam .
這些詞如find, feel, think, believe, consider, make等常可用it引導(dǎo)形式賓語，that引導(dǎo)真正賓語從句。
Eg He found it important that he learned to operate computer.
但應(yīng)注意有些動(dòng)詞只帶it + that從句而不帶復(fù)合賓語。
Eg I shall see to it that he is taken good care of when you are absent.
I take it that he approves.
另外在in, but, except等少數(shù)幾個(gè)介詞后可跟由that引導(dǎo)的賓語從句，已形成固定結(jié)構(gòu)in that（因?yàn)椋゜ut that（要不是…只是），except that（除了）
三。同位語從句
The news that Beijing will hold the 2008 Olympic Games is exciting.
Word came that China has succeeded in launching a spaceship.
同位語從句一般由that引導(dǎo)，也可由what,which,who, when,where, why,how,whether, if 引導(dǎo)。一般在fact,news, evidence, concept, belief, doubt, thought,word, idea, truth, opinion,message,order, proof, suggestion,sign等抽象名詞后，由連接詞that引導(dǎo)同位語從句，說明抽象名詞的內(nèi)容或意義。That不充當(dāng)任何句子成分，只起連接作用，雖然沒有具體含義，但不能省略。
Eg The suggestion that we should build a nuclear power station is to be discussed at the meeting.
四。定語從句
all作主語時(shí)，定語從句由that引導(dǎo)，what是不能引導(dǎo)定語從句的。通常只能由that引導(dǎo)定語從句的情況包括。
（1）先行詞為形容詞的級
（2）先行詞為序數(shù)詞
（3）先行詞中有不定代詞something,anyting, nothing, everything以及all,little等
注意下列情況一般也用that引導(dǎo)。如：
He is not the man that he was
Do you remember what happened the day that he came ?
在the day ,the morment 等時(shí)間詞后面 ，that引導(dǎo)表示“此時(shí)”或“在此期間”
五。狀語從句
that一般不單獨(dú)引導(dǎo)狀語從句，而和其他詞一起引導(dǎo)。引導(dǎo)狀語從句用on condition that〈如果〉，原因狀語從句now that〈既然〉結(jié)果狀語從句用so… that ,such… that, so that,目的狀語從句用so that（為了），for fear that（以防），in order that（為了）
Eg Now that you have enough money, you should buy a house for your own.
You will certainly succeed on condition that you keep on trying .
Study hard so that you can pass the entrance examination .
It was raining so heavily that we had to put off the sports meet .
六。替代。
在英語中為避免重復(fù)，常用that代替前面的不可數(shù)名詞。用the one代替前面的單數(shù)可數(shù)名詞。用those ones代替前面的復(fù)數(shù)名詞。
Eg By1990, production in the area is expected to double that of 1980 .