Air pollution is getting more and more serious, so we must take action it is too late.
A．before B．after C．until D．when
—Where is the post office?
—It's just over there, at the end of the street. You not miss it.
A．can B．must C．may D．would
is known to all is that the Diaoyu Islands have belonged to China since ancient times.
A．As B．It C．What D．That
Skiing in Taiwan is most of the time because there's very little snow there.
A．common B．necessary C．normal D．impossible
Schools in China are required to at least one “Sports Day” per academic year.
A．set aside B．set down C．set out D．set off
—May I see your driving license, please?
— ？ Did I do something wrong?
A．Why not B．What C．Who cares D．So what
