⑴ 做賓語的關(guān)系代詞常可以省略；

⑵ 關(guān)系代詞在定語從句中做主語時，從句謂語動詞的數(shù)要和先行詞一致；

⑶ 先行詞為不定代詞 all、something、nothing、anything、little等不定代詞時或是序數(shù)詞或是形容詞最高級時，關(guān)系代詞用that 來引導(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a complete 徹底的change改變in his life.

⑷ 關(guān)系代詞在定語從句中亦可用作介詞的賓語，如: whom (指人)、which (指物)

   this is the book for which you asked.  尋找

   the person from whom the message came來自 did not say his name.

4、非限定性從句。

如果缺少了不會影響全句的主要思想，前面一般有逗號，翻譯時常譯成兩個句子，that和why一般不用于非限定性定語從句，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