that是个常见词，用法广泛。作为连词，它可以引导不同种类的从句。现就此探讨归纳如下：

一、that引导名词性从句

所谓名词性从句，指的是主语从句、宾语从句、表语从句和同位语从句。that引导名词性从句时，它本身不作任何句子成分，也没有任何词义，只起连接作用。

1. that引导主语从句

可以将that引导的主语从句放在谓语动词前面，也可在句首用形式主语it，而将that引导的主语从句后置。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惊。

（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，王教授明天下午要给我们讲课。

注意：that常在下边的句型中引导主语从句：It is / was + 动词的过去分词 + that从句。例如：

（3）It is said that the book has been translated into several foreign languages .

据说，那本书已被译成了几种外语。

（4）It is reported that as many as 250,000 people lost their homes because of the earthquake .

据报道，多达25万人因地震而无家可归。

2. that引导宾语从句

引导宾语从句的that，在口语和非正式语体中常可省略。如果句中有两个或两个以上的宾语从句，则除第一个that可省略外，其它宾语从句中的that都不能省略。例如：

（1）He suggested (that) we should keep on trying .

他建议我们继续努力。

（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 .

我们必须相信，我们每个人都能把每件事做好；而且我们领悟此事是何事之后，我们就必须努力做下去，直到成功为止。

3. that 引导表语从句

that引导的表语从句，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难。

（2）The reason why so many people were killed in the big fire is that the building was built without any fire escapes .

这么多的人在大火中丧生，其原因是那座楼房里没有太平门。

4. that引导同位语从句

同位语从句是对前面名词的具体内容所作的详细阐述。例如：

（1）We are surprised at the fact that the children did it on their own .

听说孩子们独立做那件事，我们感到吃惊。

（2）They expressed their hope that they would like to go to visit the Great Wall .

他们表达了他们想去参观长城的愿望。

二、that引导定语从句

that引导定语从句时，是关系代词，它可指人（相当于who , whom ），也可指物（相当于which）。that在定语从句中可作主语，也可作宾语（作宾语时常可省略）。当定语从句修饰的先行词既有人又有物时，只能用that引导定语从句。例如：

1. This is the museum (that / which) they visited last month .

这就是他们上个月参观的博物馆。

2. They are going to the village that / which lies south of the mountain .

他们将去山南边的那个村庄。

3. The man (that / who / whom) I shook hands with just now is one of my old classmates .

刚才和我握手的人是我过去的一位同班同学。

4. Do you still remember the things and persons that we talked about at the meeting last month ?

你还记得上月我们在会上谈到的人和事吗？

三、that用在强调句型中

强调句型的结构为：It is / was … that … 。如果被强调的是人，可用who代替that。如果被强调的是时间状语、地点状语或原因状语，则一般都用that。例如：

1. It was on July 30 that they decided to meet again .

就是在六月三十日他们才决定再一次见面的。

2. It is in the classroom that we usually have our classes .

我们通常是在教室里上课。

3. It was Ms King who / that pretended to be a man in order to get a job .

为找工作而女扮男装的是金女士。