在英语语法中，从属连词和关系副词都是用来引导从句的词语，但它们在使用方法和作用上有着不同的区别。
从属连词
从属连词用来连接主句和从句，从属连词引导的从句一般不能单独成句，它需要依附于主句才能有完整的意义。常见的从属连词有：
- that
- whether
- if
- because
- since
- when
- while
例如：
- I know {that} she is coming.
- Can you tell me {whether} you will attend the meeting?
- {If} it rains, we will stay at home.
- I am happy {because} I passed the exam.
- He has been living in China {since} 2010.
- {When} I arrived, they were already there.
- He studied hard {while} his classmates were playing games.
关系副词
关系副词是用来连接主句和从句的词语，但它们同时在从句中充当了某个成分（如主语、宾语、定语等），并且可以在从句中独立成句。常见的关系副词有：
- where
- when
- why
例如：
- This is the hotel {where} we stayed last year.
- Do you remember the day {when} we met for the first time?
- That is the reason {why} he left his job.
需要注意的是，关系副词在从句中充当的成分决定了它在从句中的位置。例如，如果关系副词在从句中充当的是宾语，那么它应该放在从句的后面，而如果关系副词在从句中充当的是定语，那么它应该放在从句的前面。
综上所述，从属连词和关系副词在英语语法中有着不同的作用和使用方法，需要我们在学习和使用时加以区分和掌握。
