Question

The largest collection of coins in England was one of 200,000 silver pennies ________ over 600 years old.

[　　]

A．all of which

B．all of them were

C．all of them

D．any of which

Answer 1

答案：C
解析：

两个完整的句子之间要有连词（此句中可用and或which，后面部分加系动词），或者用独立主格（C）。