1.that用作指示代詞的意思是“那,那個”?？芍盖懊嫣岬降哪羌?也可指在空間或時間上較另一事物遠的事物或人,還可指要表明的或要提及的事物、想法等。

　2.that用作關(guān)系代詞時,指人或事物,同時又在從句中充當句子成分。that偶爾也可引導(dǎo)非限制性定語從句。

　3.that還常用以代替who, whom, which,但that...which中的that用做關(guān)系代詞的先行詞。

　4.that用作關(guān)系代詞時在下列情況下可以省略:①引導(dǎo)限制性定語從句在從句中用作賓語時; ②用在there be結(jié)構(gòu)前作主語時; ③用作表語時; ④在定語從句與先行詞之間有插入語時; ⑤在先行詞way, reason, distance, place, office等作方式狀語、原因狀語或地點狀語時。

　5.that用作連詞時可引導(dǎo)主語從句、賓語從句、表語從句、同位語從句和狀語從句。

　6.that還常引導(dǎo)間接引語或形容詞后面的從句。

　7.that在以it作形式主語的句子中或引導(dǎo)賓語從句、狀語從句時?？墒÷浴?/p>

　8.that也可用于表示愿望或遺憾。

一、引導(dǎo)名詞性從句

即引導(dǎo)主語從句、賓語從句、表語從句和同位語從句，that沒有任何意義，也不作任何句子成分，只起引導(dǎo)作用。

1. 引導(dǎo)主語從句

由于中英語言文化的差異，漢語沒有主語從句。如，“英語很重要不是人人都認同的。”漢語語法認為，“英語很重要”是主位詞組做句子的主語。而英語句子“That English is of vital importance is not acknowledged by all.”中，That English is of vital importance是主語從句。雖然that沒有任何意義，也不作任何句子成分，只起引導(dǎo)作用，但是卻不能省略。如：

That English teacher can speak fluent English is a fundamental requirement.

2. 引導(dǎo)賓語從句

引導(dǎo)賓語從句的that一般可以省略，但在以下六種情況下，一般不能省略。

（1）兩個以上的賓語從句并列時，從第二個從句開始，that 不能省略。如：

Jack was informed（that）he had been enrolled in Sun Yat-sen University，and that he should register by August.

（2）介詞后引導(dǎo)賓語從句的that 不能省略。如：

His parents expected him nothing but/except that he can make a living by himself after graduation.

（3）主句的謂語動詞與that引導(dǎo)的賓語從句之間有插入語時，that不可省略。如：

The head teacher told Jack， after a short hesitation， that he could have a day off on condition that he could make up for the missing lessons.

（4）形容詞后引導(dǎo)賓語從句的that一般不省略。如：

Marys parents are very content that their daughter has made such great progress in the final examination.

（5）在 it（形式賓語）+ adj.（補足語）+ that（賓語從句）結(jié)構(gòu)中， that不能省略。如：

Everyone believes it strange that he could pass the driving test.

（6）在直接引語中，that引導(dǎo)的賓語從句與主句隔開時，that不能省略。如：

“Im sorry to say，” he said， “that you are not the suitable person for the work.”

3. 引導(dǎo)表語從句

表語從句位于連系動詞后，引導(dǎo)表語從句的that一般不能省略。如：

My advice is that everyone be punctual for the appointment.

特別注意：下列句式中的that一般不能用because代替。

The reason why he was late for school is that he missed the early bus.

4. 引導(dǎo)同位從句

同位語從句就是在news， information， fact， word， idea等抽象名詞之后，說明其具體內(nèi)容的從句。引導(dǎo)同位語從句的that一般不能省略。如：

Based on the fact that you are enthusiastic about Chinese culture， Im writing to invite you to get involved in it.

二、引導(dǎo)定語從句

that常被用來代替關(guān)系代詞which或who，引導(dǎo)定語從句。以下幾種情況，多用that而不用which或who。

1. 當先行詞是表示事物的all， any， anything， everything， nothing或被all， any， every等修飾時。如：

Do you have anything that you are puzzled with？

All that can be done must be done.

2. 當先行詞被形容詞的最高級或序數(shù)詞修飾時。如：

It is one of the most touching movies that have been shown this month.

The first thing that we should do is to get some food.

3. 當先行詞有the only， the very， the same， the last 等修飾時。如：

The only thing that is impressive is his unforgettable experience in Beijing.

4. 當主句以who或which開頭的疑問句時。如：

Who is the girl that is delivering a speech over there？

5. 當先行詞既有人又有物時。如：

The writer and his novel that you have just talked about are really well known.

三、引導(dǎo)狀語從句

1. that 可引導(dǎo)目的狀語從句和結(jié)果狀語從句，that一般不省略。如：

The story is so touching that we will bear in our mind for a long period.

An English Speech Contest will be organized so that/ in order that students can improve their oral English.

四、用作替代詞

My seat is next to that of Marys.

The temperature in Guangdong is higher than that in Beijing.

五、用作副詞

Thanks for your encouragement， but actually my handwriting isnt that beautiful.

六、 用在強調(diào)句型中

It was what you said that sparked his motivation to work hard.

七、用在一些成語中

1. like that 像這樣

Do you usually speak to your parents like that？

2. Thats it. 說對了。

Thats it. Youve described exactly what I felt about the film.

3. Thatthat. 情況就是如此。

Well， the only task for you is to clean the blackboard in time， and thats that.

4. with that接著，然后

He said goodbye to me and with that he left.