it's price 和 the price of which的區(qū)別
Recently I bought an ancient Chinese vase,_______ was very reasonable.
A.which price
B.the price of which
C.its price
D.the price of whose
我知道答案是B,考的是定語從句.但是答案C怎么不行?
類似的還有some of them和some of which; 以及both of them和both of which的區(qū)別
比如：We have three foreign teachers,__________are from Canada.（期中的兩個）
答案應(yīng)該是two of whom,而不是 two of them.為什么?
希望英語達(dá)人們給出詳細(xì)的解答.