that是個常見詞,用法廣泛.作為連詞,它可以引導(dǎo)不同種類的從句.現(xiàn)就此探討歸納如下：一、that引導(dǎo)名詞性從句所謂名詞性從句,指的是主語從句、賓語從句、表語從句和同位語從句.that引導(dǎo)名詞性從句時,它本身不作任何句子成分,也沒有任何詞義,只起連接作用.1.that引導(dǎo)主語從句可以將that引導(dǎo)的主語從句放在謂語動詞前面,也可在句首用形式主語it,而將that引導(dǎo)的主語從句后置.例如：（1）That Mr King had been put into a women”s ward surprised his boss .= It surprised his boss that Mr King had been put into the women”s ward .金先生被安排在了女病房使他的老板很吃驚.（2）That Professor Wang will give us a lecture tomorrow afternoon is known to all .= It is known to all that Professor Wang will give us a lecture tomorrow afternoon .大家都知道,王教授明天下午要給我們講課.注意：that常在下邊的句型中引導(dǎo)主語從句：It is / was + 動詞的過去分詞 + that從句.例如：（3）It is said that the book has been translated into several foreign languages .據(jù)說,那本書已被譯成了幾種外語.（4）It is reported that as many as 250,000 people lost their homes because of the earthquake .據(jù)報道,多達25萬人因地震而無家可歸.2.that引導(dǎo)賓語從句引導(dǎo)賓語從句的that,在口語和非正式語體中常可省略.如果句中有兩個或兩個以上的賓語從句,則除第一個that可省略外,其它賓語從句中的that都不能省略.例如：（1）He suggested (that) we should keep on trying .他建議我們繼續(xù)努力.（2）We must believe (that) each one of us is able to do something well ,and that ,when we discovered what this is ,we must work hard at it until we succeed .我們必須相信,我們每個人都能把每件事做好；而且我們領(lǐng)悟此事是何事之后,我們就必須努力做下去,直到成功為止.3.that 引導(dǎo)表語從句that引導(dǎo)的表語從句,一般位于句尾,that通常不能省略.例如：（1）It seems that it is more difficult for women to get jobs than men .似乎女人找工作比男人更難.（2）The reason why so many people were killed in the big fire is that the building was built without any fire escapes .這么多的人在大火中喪生,其原因是那座樓房里沒有太平門.4.that引導(dǎo)同位語從句同位語從句是對前面名詞的具體內(nèi)容所作的詳細(xì)闡述.例如：（1）We are surprised at the fact that the children did it on their own .聽說孩子們獨立做那件事,我們感到吃驚.（2）They expressed their hope that they would like to go to visit the Great Wall .他們表達了他們想去參觀長城的愿望.二、that引導(dǎo)定語從句that引導(dǎo)定語從句時,是關(guān)系代詞,它可指人（相當(dāng)于who ,whom ）,也可指物（相當(dāng)于which）.that在定語從句中可作主語,也可作賓語（作賓語時?？墒÷裕?當(dāng)定語從句修飾的先行詞既有人又有物時,只能用that引導(dǎo)定語從句.例如：1.This is the museum (that / which) they visited last month .這就是他們上個月參觀的博物館.2.They are going to the village that / which lies south of the mountain .他們將去山南邊的那個村莊.3.The man (that / who / whom) I shook hands with just now is one of my old classmates .剛才和我握手的人是我過去的一位同班同學(xué).4.Do you still remember the things and persons that we talked about at the meeting last month 你還記得上月我們在會上談到的人和事嗎?三、that用在強調(diào)句型中強調(diào)句型的結(jié)構(gòu)為：It is / was … that … .如果被強調(diào)的是人,可用who代替that.如果被強調(diào)的是時間狀語、地點狀語或原因狀語,則一般都用that.例如：1.It was on July 30 that they decided to meet again .就是在六月三十日他們才決定再一次見面的.2.It is in the classroom that we usually have our classes .我們通常是在教室里上課.