问题补充:
Mary went to the box office at lunch time, but all the tickets out.
A. would sell
B. had been sold
C. have been sold
D. was selling
答案:
A. would sell
(答案→)B. had been sold
C. have been sold
D. was selling
解析:考查时态。句意:Mary在吃午饭的时候去了售票处,但是所有的票都被卖完了。根据句意说明所有的票被卖完是在她去办公室之前,而她去办公室使用了一般过去时,那么票买完使用过去完成时。根据句意还要使用被动语态。故B正确。