Question

None of them knew what happened __________we told them about it.

A．since

B．after

C．until

D．while

Answer 1

C

考查连词用法。since自从，after在…之后，until直到，while当…时候，句意：他们当中没有一个人知道出什么事了直到我告诉他们。根据语境应选C。