问题
选择题
No one ______ this building without the permission of the police .
A is leaving B is to leave C has left D will be leaving
答案
答案：B
考察be to do 用法。Be to do用于否定句，表示“禁止”，相当于mustn’t。结合句意可知B正确。句意：没有警察的允许，任何人都不得离开大楼。
