问题补充:
No one the building without the permission of the policeman.
A. is leaving
B. will be leaving
C. has left
D. is to leave
答案:
A. is leaving
B. will be leaving
C. has left
(答案→)D. is to leave
解析:考查将来时的表达法。本句中的be to do sth表示计划的事情;或者表示注定要做某事;也可以表示命令做某事,相当于have to, must,should;句意;没有警察的允许没有人可以进入大楼。表示的是一种命令。故D正确。