He talked about the classmates and the school （ ） he had visited.
（A）who
（B）that
（C）which
（D）about which
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
The reason （ ） he didn't come was （ ） he was ill. 选项：
（A）why; that
（B）that; why
（C）for that; that
（D）for which; what
