能引导三种英语从句的“连词”

总体上讲，英语的从句只有三种：状语从句、定语从句和名词性从句（主语从句、宾语从句、表语从句和同位语从句），在主句中担任一种句子成分。为了区别引导各种从句的 “连词”，我们通常把引导状语从句的连词叫做“连词”，引导定语从句的连词叫做“关系词”，而把引导名词性从句的连词叫做“连接词”。下列连词可以引导三种不同的从句。

一.When

1.    状语从句

When (=At the time when) the earthquake broke out, We were playing basketball on the sports ground.发生地震时，我们正在操场上打篮球。

2.    定语从句

I’ll never forget the day when (=on which) I joined the League.我永远也忘不了我入团的那一天。

3.    名词性从句

I want to know when (=the time when) the meeting will begin.我想知道会议将在什么时间开始。（宾语从句）

When 在引导名词性从句时相当于：the time when（先行词+关系词）；引导状语从句时相当于：介词+ the time when（介词短语+关系词）, 例如：

Please tell me when (the time when) the the sportsmeet ended.请告诉我运动会是什么时候结束的。

When (At the time when ) I woke up this morning, it was raining hard.我早上醒来时正下着大雨。

二.Where

1. 状语从句

This is the office where (=in which) our parents once worked.这是我父母曾经工作过的办公室。

2. 定语从句

Put this book where (=at the place where)it used to be.把这本书放回原处。

3.名词性从句

Where (=The place where) we are going to meet has not been decided.我们碰头的地点还未定。（主语从句）

where在引导名词性从句时相当于：the place where（先行词+关系词）；引导状语从句时相当于：介词+ the place where（介词短语+关系词）,例如：

We must know where (the place where) the treasure was hidden at present.现在我们要必须知道宝藏藏在什么地方。

We were seated where (near the place where) a post stood in the hall.我们被安排坐在大厅的立柱附近。

三.That

1.定语从句

We’ve done all that can be done.能做的我们都做了。

2.状语从句

Johnson was so kind-hearted that he adapted dozens of orphans.约翰逊心肠真好，收养了几十个孤儿。（结果状语从句）

3.名词性从句

It is reported that over 10,000 people were killed in the earthquake.据报道在那次地震中死去了一千多人。（主语从句）

I sincerely hope that you can join us in the project.我衷心希望你能参加这个项目。（宾语从句）

The reason why she didn’t attend the seminar was that she hadn’t got informed.她没参加研讨会的原因是她没得到通知。（表语从句）

There is no doubt that we shall have another bump harvest this year.毫无疑问，今年我们又会有个好收成。（同位语从句）

that在引导状语从句和名词性从句时，本身无意义，在从句中不担任任何成分; 而在引导定语从句时必须担任句子成分，指代先行词。（参见上面的例句）

四. As

1.状语从句

As his mother was ill in hospital, he was absent from the conference.他因母亲生病住院而缺席了那次会议。（原因状语从句）

As we were young, most of us had a poor life.我们小时候，大多数人都过着贫穷的生活。（时间状语从句）

A tortoise does not run so fast as a hare does.乌龟跑不到兔子快。（比较状语从句）

Much as I like you, I’ll not marry you.虽然我很喜欢你，但我不想嫁给你。（让步状语从句）

Do it as I do it.照我做的样子做。（方式状语从句）

2. 定语从句

As we all know, the earth is not round.众所周知，地球不是圆的。

He spent as much money as he could (spend) to buy books.他竭尽所有买书。

I want to buy the same dictionary as you have.我想买一本跟你的一样的词典。

Such people as are present at today’s ceremony are outstanding in our city.出席今天这个仪式的人都是本市的杰出人物。

3. 名词性从句

It looks as though it is going to snow.老天看上去要下雪了。（表语从句）

As if, as though在引导表语从句时同引导方式状语从句一样，谓语可以用虚拟语气。例如：

It seems as if a chopstick were bent when it is in a glass of water. 当一根筷子放在一杯水里时，就好像是弯的。（表语从句）