1、用做定語(yǔ)的從句叫做定語(yǔ)從句，一般修飾名詞或代詞。被修飾的名詞或代詞，我們稱(chēng)之為先行詞，定語(yǔ)從句放在先行詞后。定語(yǔ)從句可以分為限制性定語(yǔ)從句和非限制性
定語(yǔ)從句。
⑴ 做賓語(yǔ)的關(guān)系代詞常可以省略；
⑵ 關(guān)系代詞在定語(yǔ)從句中做主語(yǔ)時(shí)，從句謂語(yǔ)動(dòng)詞的數(shù)要和先行詞一致；
⑶ 先行詞為不定代詞 all、something、nothing、anything、little等不定代詞時(shí)或是序數(shù)詞或是形容詞最高級(jí)時(shí)，關(guān)系代詞用that 來(lái)引導(dǎo)，強(qiáng)調(diào)句中也可用that,
have you anything that you need?
the first thing第一件事情that we should do is to clean打算 the room.
it was the largest map that i ever曾經(jīng) saw.
it was liberation 解放that brought about 引起帶來(lái)a complete 徹底的change改變in his life.
⑷ 關(guān)系代詞在定語(yǔ)從句中亦可用作介詞的賓語(yǔ)，如: whom (指人)、which (指物)
this is the book for which you asked. 尋找
the person from whom the message came來(lái)自 did not say his name.
4、非限定性從句。
如果缺少了不會(huì)影響全句的主要思想，前面一般有逗號(hào)，翻譯時(shí)常譯成兩個(gè)句子，that和why一般不用于非限定性定語(yǔ)從句，也不能省略任何關(guān)系副詞。
sunday星期日 is a holiday假期, when people do not go to work.
i picked up撿起，拾起 the apples, some of which are badly bruised.碰傷