which在名詞性從句的用法：
1.賓語(yǔ)從句
which是一個(gè)連接代詞,在賓語(yǔ)從句中可以充當(dāng)主語(yǔ),賓語(yǔ)或定語(yǔ).意思是“哪一個(gè)”如：I don't know which bike belongs to my father.
I wonder which is better ,this one or that one?
He asked me which I liked best.
2.主語(yǔ)從句
which 在主語(yǔ)從句中的用法與賓語(yǔ)從句相類似.
which boy she likes best is still a mystery.
Which students will be sent to take part in the sports meeting hasn't been decided.
3.表語(yǔ)從句
which 在表語(yǔ)中的用法與主語(yǔ)從句和賓語(yǔ)從句的用法也相似.
如：His question is which student is the best at English.
The question is which place he wants to go to .
4.同位語(yǔ)從句
which在同位語(yǔ)從句中的用法不多,只用在某些名詞的后面,常見的有idea.
I have no idea which picture is the most beautiful of all.
順便講一下,what引導(dǎo)的名詞性從句,也是連接代詞,但表示的是泛指的東西；which指的是在一定的范圍內(nèi),哪一個(gè).