从属连词( les conjonctions de subordination)，是连词的一种，用来引导名词性从句和状语从句，并在它们之间建立从属关系。连词用于引导从句以形成句子的一部分或修饰句子的构成要素。由从属连词所引导的句子叫从句，而含有从句的句子叫作复合句。

连词(conjunction):用于引导从句以形成句子的一部分或修饰句子的构成要素，连词是连接单词,短语,从句或句子的一种虚词。

从属连词(subordinating conjunction)

从属连词这种连词是用以引导名词性从句和状语从句的. 由从属连词所引导的句子叫从句,而含有从句的句子叫作复合句。

大致可分为两大类：

1、名词性从句里的从属连词

that （无词义，不做成分）

if，whether （表达是否的意义，但不做句子成分）

2、状从里的从属连词，before，after，since，if，because，though等。

在英语词类中，连接词可说是最容易掌握的一种。

从结构上说，英语连接词分两大类：并列连词（coordinating conjunctions）和从属连词（subordinating conjunctions）。

并列连词连接两个或两个以上地位平等的字、词组或分句。例如：

(1) Air and water are indispensable to me.

(2) She likes going out with friends or playing outdoor games.

(3) Most workers have a good income, so they look very happy.

从属连词连接两个或两个以上的分句，形成复杂句中的从属分句。例如：

(4) He said that he did not want to go .

(5) Many things have happened since I last saw him.

(6) You may come if you want to.

从属连词用来连接各种从句。until(till)直到，在用until表达时间状语的句子中，主句中的动词是要十分小心去选择的。如动词是持续性动词，它要用肯定句，如：I studied hard until 12 o'clock last night.如果动词是瞬间截止性动词，则要用否定句，如:He didn't go to bed until his mother came back.由since,for,by,before, 来引导的时间状语从句。since 引导的时间状语是动作的开始时间，如:I have studied English since 1990.而by引导的时间状语通常是动作的结束时间，如：I had learned 25 English songs by the end of last term.

上述连词的用法，看起来不难，但错误也难免。下面是些好例子：

(1) This book may be used both as a text as well as a reference book.

这里的“as well as”和“both”不能搭配，应该将“as well as ”改为“and”，使“both.......and......”变成关联连词（ correlative conjunction）

(2) He not only speaks Mandarin but also English.

这里的“not only”应该移到“speaks”后面，使这个动词兼顾两个独立宾语：“Mandarin”和“English”。

(3) Although he is fat, but he is very weak.

英语里的“although”和“but”是不见面的 ，因此这句里的“ but”要去掉，不然“although”就要去掉。

(4) Jim is not so strong like you.

这里的“not so”必须和“as”连成一体；介词“like”是不适宜的。

(5) No sooner had we reached our destination, they left.

No sooner had we reached our destination than they left.

这句子的意思也可透过“as soon as”反映出来：

“As soon as we reached our destination, they left.”

(6) I took a taxi and which took me to the station.

这里的并列连词“and”是多余的，必须去掉。如果要保留“and ”也可，但是形容词分句里的关系代词“Which”要改成主语“it” ，使整个句子变成并列分句如下：

I took a taxi and it took me to the station.

(7) My friend came up to me and held my hand, said good-bye excitedly.

这里的“and”应该用来连接最后两个谓语才对：

My friend came up to me, held my hand, and said good-bye excitedly.

不然，就要把“said”改成“saying”。

“saying”起主要作用。