| 在句子中起定语作用，修饰主句中的某一名词或代词的句子称为定语从句 被定语从句修饰的名词、代词称为先行词；引导定语从句的词称为关系词（考点：关系词） |
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|---|---|---|---|---|---|
| 关系代词（在定从中充当主语或宾语，作宾语时可省略） | |||||
| 关系代词 | 先行词 | 充当成分 | 例句 | ||
| who | 人 | 主语、宾语 | The boy who is in the office is my brother. | ||
| whom | 人 | 宾语 | The man whom they are talking with is Jack. | ||
| that | 人/物 | 主语、宾语 | This is the dress that I bought yesterday. | ||
| which | 物 | 主语、宾语 | I like the dress which is beautiful. | ||
| whose | 人/物 | 定语（……的） | I like the room whose windows are big. | ||
| 【注意】 | ①介词后面用whom 或which，且不能省略；②先行词既指人又指物只能用that | ||||
| 关系副词（在定从中充当状语，定从本身不缺主语和宾语时用关系副词） | |||
|---|---|---|---|
| 关系副词 | 先行词 | 充当成分 | 例句 |
| when | 时间 | 时间状语 | Tom remembers the day when he met Jerry. |
| where | 地点 | 地点状语 | Tom remembers the park where he met Jerry. |
| why | 原因 | 原因状语 | That is the reason why he was late for school. |