28. If ________ in the elevator, please press the emergency button immediately.
A
trapped
B
trapping
C
having trapped
D
to be trapped
23. ______ more about our university courses, write to this address.
30. A notice will be put up_____ information about the closing dates for entering exams.
32. ––Do you mind if I smoke here?
––I suggest you go to the separate room ______ for smokers.
句意：如果被困在电梯里，请立刻按响紧急情况按钮。If trapped的完整形式为：if you are trapped。故选A。
倒装与省略
判断结构
抓不住要点
难度适中