作句子主語(yǔ)的從句叫主語(yǔ)從句。主語(yǔ)從句通常由從屬連詞that,whether,if和連接代詞what,who,which,whatever,whoever以及連接副詞how,when,where,why等詞引導(dǎo)。that在句中無(wú)詞義,只起連接作用;連接代詞和連接副詞在句中既保留自己的疑問(wèn)含義、又起連接作用,在從句中充當(dāng)從句的成分。例如:
What he wants to tell us is not clear. 他要跟我們說(shuō)什么,還不清楚。
Who will win the match is still unknown. 誰(shuí)能贏得這場(chǎng)比賽還不得而知。
It is known to us how he became a writer. 我們都知道他是如何成為一名作家的。
Where the English evening will be held has not yet been announced. 英語(yǔ)晚會(huì)將在哪里舉行,還沒(méi)有宣布。
有時(shí)為避免句子頭重腳輕,常用形式主語(yǔ)it代替主語(yǔ)從句作形式主語(yǔ)放于句首,而把主語(yǔ)從句置于句末。主語(yǔ)從句后的謂語(yǔ)動(dòng)詞一般用單數(shù)形式。常用句型如下:
(1) It + be + 名詞 + that從句
(2)It + be + 形容詞 + that從句
(3)It + be + 動(dòng)詞的過(guò)去分詞 + that從句
(4)It + 不及物動(dòng)詞 + that 從句
另注意在主語(yǔ)從句中用來(lái)表示驚奇、不相信、惋惜、理應(yīng)如此等語(yǔ)氣時(shí),謂語(yǔ)動(dòng)詞要用虛擬語(yǔ)氣“(should) +do”,常用的句型有:
It is necessary (important, natural, strange, etc.) that …
It is a pity (a shame, no wonder, etc.) that…
It is suggested (requested, proposed, desired, etc.) that…
三、賓語(yǔ)從句
名詞句用作賓語(yǔ)的從句叫賓語(yǔ)從句。引導(dǎo)賓語(yǔ)從句的關(guān)聯(lián)詞與引導(dǎo)主語(yǔ)從句表語(yǔ)從句的關(guān)聯(lián)詞大致一樣,在句中可以作謂語(yǔ)動(dòng)詞或介詞及非謂語(yǔ)動(dòng)詞的賓語(yǔ)。
1. 由連接詞that引導(dǎo)的賓語(yǔ)從句
由連接詞that引導(dǎo)賓語(yǔ)從句時(shí),that在句中不擔(dān)任任何成分,在口語(yǔ)或非正式的文體中常被省去,但如從句是并列句時(shí),第二個(gè)分句前的that不可省。例如:
He has told me that he will go to Shanghai tomorrow. 他已經(jīng)告訴我他明天要去上海。
We must never think (that) we are good in everything while others are good in nothing. 我們決不能認(rèn)為自己什么都好,別人什么都不好。
注意:在demand、order、suggest、decide、insist, desire, request, command等表示要求、命令、建議、決定等意義的動(dòng)詞后,賓語(yǔ)從句常用“(should)+ 動(dòng)詞原形”。例如:
I insist that she (should) do her work alone. 我堅(jiān)持要她自己工作。
The commander ordered that troops (should) set off at once. 司令員命令部隊(duì)馬上出發(fā)。
2. 用who,whom, which, whose, what, when, where, why, how, whoever, whatever, whichever等關(guān)聯(lián)詞引導(dǎo)的賓語(yǔ)從句相當(dāng)于特殊疑問(wèn)句,應(yīng)注意句子語(yǔ)序要用陳述語(yǔ)序。例如:
I want to know what he has told you. 我想知道他告訴了你什么。
She always thinks of how she can work well. 她總是在想怎樣能把工作做好。