that是英語中十分常見的單詞，用法靈活多樣，是英語中最常用的詞彙之一。正因為它是我們認為自己最熟悉的單詞，反而容易忽視它。在考研英語中，對that的考查包括三個方面：（1）that作指示代詞的用法；（2）that作連詞引導各類從句時，需要準確辨別從句類型。
一、that作限定詞或代詞
that可以作限定詞或代詞連接名詞或名詞短語，也可單獨使用，用以指代人或者物。此外，that不僅可以指代單獨的人或物，還可以指代一句話。
例：Furthermore, in the early days of long line fishing, a lot of fish were lost to sharks after they had been hooked. That is no longer a problem, because there are fewer sharks around now. [2006, text3]
分析：
A.分析句子結構。Furthermore, in the early days of long line fishing, a lot of fish were lost to sharks //after they had been hooked. That is no longer a problem, //because there are fewer sharks around now.
第一個句子的主句為a lot of fish were lost to sharks，介詞短語in the early days of long line fishing作狀語，after引導時間狀語從句。第二個句子主句是That is no longer a problem, that為代詞，because引導原因狀語從句。
B.分析that指代。that指代第一句話，「a lot of fish were lost to sharks after they had been hooked」，其中after引導時間狀語從句。
C.譯文：而且，在使用多鉤長線捕魚的初期，許多魚被鉤住後又被鯊魚奪走。這不再是一個問題，因為附近的鯊魚更少了。
二、that作副詞表示程度，相當於so
例：It isn’t all that cold.天沒有那麼冷。
三、that作連詞引導各類從句
（一）that引導名詞性從句
that後面連接一個完整的陳述句，可以位於主語、賓語、表語或同位語的位置，分別引導主語從句、賓語從句、表語從句和同位語從句。此時，that沒有實意，而且不在從句中做任何成分。that引導主語從句和同位語從句時不可以省略。
例1：That the plates are movingis now beyond dispute.（主語從句）
地球板塊是在漂移的，這一事實毋庸置疑。
例2：The truth isthat everyone should take care of orphan, not just the authorities.（表語從句）
事實是，所有人都應該照顧孤兒，而不僅僅是完全由政府承擔。
例3：All people believedthat it was right to rescue the temple.（賓語從句）（註：that可以省略）
所有人都認為拯救古廟是正確的。
例4：The students expressed their hopethat they could be admitted by that university.（同位語從句）
學生們表達了他們向被這所大學錄取的願望。
（二）that引導定語從句
that引導定語從句，在從句中充當主語、表語或者賓語，既可以指代人，也可以指代物。that在定語從句中作賓語時，引導詞that可以省略。
例1：The professor that you admire most will visit our university next month.
你敬仰的那個教授下月會到我們學校參觀。
例2：This is one of the subways that will be put into use in two years.
這是未來兩年內將開通的地鐵之一。
例3：I have nothing that is worth reading.
我沒有什麼值得一讀的東西。
（註：當先行詞中有不定代詞、形容詞最高級、序數詞或者先行詞被the only，the very等限定詞修飾等情況下，定語從句引導詞也只能用that。）
（三）that與其他單詞結合引導狀語從句
that可以和其他單詞結構共同引導狀語從句，例如such...that，so...that等引導結果狀語從句，in order that，so that等引導目的狀語從句，in that，now that，on the grounds that等引導原因狀語從句，suppose/supposing/assume/assuming/provided/providing that，on condition that等引導條件狀語從句等。
例1：She has madesuchrapid progressthatbefore long she could pass the exam.
她進步很快，不久就能通過考試的。
例2：You should make full use of this opportunityso thatyou can get rich experience.
你應該充分利用這次機會，以便獲得豐富的經驗。
例3：Supposing thatyou were in my position, what would you do?
如果你在我的位置，你會怎麼做？
例4：On condition thatyou were lost in the desert, you should ask for help as soon as possible.
如果你在沙漠中迷路，你應該儘早尋求幫助。
（四）that引導強調句
「It is/was+被強調部分+that從句」是高頻使用的一種強調句型，其中被強調部分可以作從句的主語、賓語和狀語等。強調句中去掉「it is/was」和「that」後，句子成分和語義仍然完整。
例：It was after the war was over that Einstein was able to come back to his research work again.
戰爭結束後愛因斯坦才能重新進行他的研究工作。
(責任編輯：張嬋)