Question

 (2011年东北三校模拟)There are 51 students in Class Three，________failed in the test.

A．all of which                         B．all of them

C．none of whom                     D．none of them

Answer 1

解析：选C。考查定语从句。后半句是非限制性定语从句，修饰先行词students，应用whom引导。因为前后两句之间没有并列连词，所以B、D两项不正确。