1．—I'm sorry, but there's no smoking in this section on the train.
—Oh, I ________ that, and I won't again.
A．don't know B．didn't know
C．won't D．haven't known
答案与解析：B 句意：——很抱歉，但这是无烟车厢。——哦，我之前不知道，我不会再抽烟了。“不知道”发生在“被提醒”之前，故用一般过去时。
2．—Why didn't you turn up at the meeting?
—I ________ for a longdistance call from my father in England.
A．waited B．had waited
C．was waiting D．have been waiting
答案与解析：C 句意：——你为什么没出席会议？——我当时正在等在英国的爸爸打来的长途电话。根据题意可以判断wait发生在“开会”(过去时)时，用过去进行时。
