the word “before”—begins— —with—“b”
Are you excited——about going to Beijing?
你对于去北京感到兴奋吗?
we should learn from the soldiers——who help people in Wenchuan after the earthquake
我们应该像在汶川地震中救人的军人们学习.
他们离开上海两个星期了
they have —been— —away— —from—Shanghai for two weeks
那地震造成许多死亡
the earthquake cause a lot of —death—
you—B—go now don't you?
A must B have to C had to D must have to
There used to be a tall tree in front of our classroom,didn't there?（反义疑问句）