在英语语法中，名词性从句是指在句子中担任名词成分的从句。引导名词性从句的词叫做引导词，而它们的种类及用法则是我们需要了解的知识点。
引导名词性从句的关系词
1. that
“that”是用得最为频繁的一个引导名词性从句的关系词，它可以引导主语从句、宾语从句、表语从句和同位语从句。例如：
- 主语从句：That he is coming is good news.
- 宾语从句：I know that he is coming.
- 表语从句：My belief is that he is coming.
- 同位语从句：The fact that he is coming is good news.
2. who/whom
“who”和“whom”都可以引导名词性从句，用来表示人。其中“who”用于主语从句和表语从句，而“whom”用于宾语从句。例如：
- 主语从句：Whoever told you that is lying.
- 宾语从句：I don’t know whom she is talking to.
- 表语从句：The winner will be whoever finishes first.
3. which/that
“which”和“that”都可以引导名词性从句，用来表示物品或事物。它们可以引导定语从句和宾语从句。例如：
- 定语从句：The book that I lent you is very interesting.
- 宾语从句：I don’t know which one to choose.
4. whose
“whose”用来引导名词性从句，用来表示某人或某物的所有关系。例如：
- The boy whose father is a doctor wants to be a doctor too.
总结
以上就是引导名词性从句的关系词的种类及用法。在实际应用中，我们需要根据句子的结构和意思来选择正确的引导词，才能使句子更加准确和流畅。
