在英语中，名词性从句的引导词有：that，which，who，whom，whose和what。"That"常用于引导限定性从句，"which"用于非限定性从句，"who","whom","whose"用于修饰人的名词性从句，而"what"则用于引导主语或宾语从句。掌握这些连接代词的用法有助于更好地理解和使用名词性从句。
常见的连接代词有：that, which, who, whom, whose以及what。它们分别引导不同类型的名词性从句。
That
That通常用来引导限定性从句，即从句对主句的内容进行了限定或者说明。例如：
- The book that I borrowed from the library is very interesting.
在这个句子中，“that I borrowed from the library”是一个限定性从句，它对“the book”的范围进行了限定。
Which
Which通常用来引导非限定性从句，即从句对主句的内容进行了解释或者补充。例如：
- I bought a new car, which is very comfortable to drive.
在这个句子中，“which is very comfortable to drive”是一个非限定性从句，它对“a new car”的特点进行了补充。
Who/Whom/Whose
这三个连接代词都用来引导修饰人的名词性从句。
- Who用来引导主语从句，例如：The person who called me yesterday was my old friend.
- Whom用来引导宾语从句，例如：I met a girl whom I had never seen before.
- Whose用来引导定语从句，例如：The man whose car was stolen called the police.
What
What通常用来引导主语从句或者宾语从句，并且代表着一件事情或者一件事物。例如：
- What you said just now is not true. （主语从句）
- I don't know what he is thinking about. （宾语从句）
