一that 引導的名詞性從句
首先,連接代詞that除引導第一個賓語從句時可以省略外,引導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.
以上四個句子中,that 分別引導主語從句,表語從句,同位語從句和賓語從句,除在第四個例句中第一個that 可以省略外,其他的that 均不可省略.其次,在引導名詞性從句時,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引導的主語從句才是整個句子的真正主語,that在句中不作任何成分.最后,在引導名詞性從句時,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.在以上兩個考例中,that僅起引導同位語從句的作用,沒有任何詞匯意義.綜上所述,that 在引導名詞性從句時具有三大特點：不可省略,不作成分,沒有詞義.
二． what引導的名詞性從句
首先,what 引導名詞性從句時,what 在句中不省略.這一用法與that引導名詞性從句時的用法不盡相同.
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在該句中引導表語從句,但在句中不可省略.其次,what 引導名詞性從句時,具有詞匯意義.這是what 與that 引導名詞性從句的重要區(qū)別之一,What 一般指“----的東西/事情/人/時間/地點等”.
例如：① Do you have any idea what is actually going on in the classroom?what在該句中引導同位語從句并作這個同位語從句的主語,詞義為“----的東西、事情”,整個句子的漢語意思是“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.這是一個強調(diào)句型,被強調(diào)的部分是由what引導的兩個主語從句,what在句中的詞義為“----的東西、事情”,整個句子的漢語意思是“關鍵要看你做什么而不是說什么”.最后,what 引導名詞性從句時不僅只起引導作用,同時還要作句中的某個句法成分.這一點是what 在引導名詞性從句時與that 用法區(qū)別的關鍵所在.
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,是一個強調(diào)句型作賓語的典型考例,被強調(diào)的成分what 在句中不僅只起引導賓語從句的作用,同時在賓語從句中作makes 的主語.
② A modern city has been set up in what was a wasteland ten years ago.在這個句子中,what 引導的從句作了介詞in 的賓語,同時what 又在賓語從句中充當主語,意思是“……的地方”.值得注意的是,在引導名詞性從句時,that 引導的句子一般不作介詞的賓語,相反,由what 引導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.綜上所述綜上所述綜上所述綜上所述,what 在引導名詞性從句時具有三大特點：不可省略,作成分有詞義.