名词修饰常常由关系代词引导：Which That Who Whose Whom Where When

　　对于这些关系代词的使用有一定限制，例如：who 和whom 要修饰人，而which 则一定修饰物，而在GAMT的语法中,that 也不能修饰人，所以修饰人的词有Who, Whose or Whom ，而That 和 Which 则无法修饰人：

　　◆ Wrong: The scientists THAT made the discovery were rewarded.

　　◆ Right: The scientists WHO made the discovery were rewarded.

　　而Which 或whom 可以跟在介词后面:

　　the canal through which water flows; the senator for whom we worked.

　　Who 在从句中作主语，而whom 则作动词或介词的宾语：

　　◆ Wrong: The security guard WHO we met was nice.

　　◆ Right: The security guard WHOM we met was nice.

　　That 和 whom 从句中作宾语时可以省略：

　　◆ Right: The movie THAT we watched last Friday was scary.

　　◆ Right: The movie we watched last Friday was scary.

　　where可以用来修改地方名词，area, site, country or Nevada ，但是无法修饰“隐喻”地方的词如：condition, situation, case, circumstances, or arrangement，而要修饰这些词则应该用in which ：

　　◆ Wrong: We had an arrangement WHERE he cooked and I cleaned.

　　◆ Right: We had an arrangement IN WHICH he cooked and I cleaned.

　　When 可以指代事件或时间，如：period, age, 1987, or decade ，这里in which 也可以替换when.