引导宾语从句的引导词主要有三类，连词，代词，和副词，这三类下又有不少的划分，在学习的过程中难免令人难以记忆，沪江小编梳理这三类引导词及其用法，并附上一些例句，希望能给学习者们带来帮助。
三类引导词：
连词：that ,whether, if
代词：who, whose, what ,which
副词：when ,where, how, why 等。
一.连词
①that:that 在大多数情况下可以省略，但在以下几种情况下不可以省略：
1.动词后接多于两个由that引导的宾语从句时，第一个that可省，但后面的that不可省
eg.He said (that) you were too young to understand the matter and that he was asked not to tell you.
2.当主句的谓语动词与that宾语从句之间有插入语时，that一般不可省
eg.Just then I noticed, for the first time, that he prepared to talk to us.
3.当that从句是双宾语中的直接宾语时，that不可省
eg.I can’t tell him that his mother died.
4.当that置于句首时
eg.That our team will win，I believe.
② whether&if ：一般情况下两者可以互换，但在以下几种情况下两者不能互换：
只能用whether：
1. 在带to的不定式前
eg.We decided whether to help him.
2. 在介词的后面
eg.I’m thinking of whether we should help him.
3. 在动词后面的宾语从句时
eg. We discussed whether we should help him.
4. 直接与or not连用时
eg. I can’t say whether or not they will help him.
只能用if：
1.if引导的表假设的从句：
eg. He will be saved if we help him.
2.if引导的表否定的从句:
eg. He asked if I didn’t help him.
3. 直接使用even if和as if
eg. He talks as if he has known all about it.
二.连接代词：who,whom,whose,which,what
eg. Can you tell me who you want to help?
三.连接副词有：when,where,why,how等
eg. All of us don"t know where he lives.
以上就是小编为大家整理的宾语从句的三类引导词了，内容比较多，不知道大家有没有被绕晕呢？其实啊，虽然这些知识点看上去复杂，但都是在日常学习中非常常见的内容，只要平常学习时多留个心，将学习重点放到整理和梳理上，理清思路，就能慢慢掌握知识点了。
