我国公安机关和人民警察的宗旨就是打击犯罪，保护人民的生命和财产的安全。 ( )
参考答案：错
_______ a reply, he decided to write again.[ ]
A. Not receiving
B. Receiving not
C. Not having received
D. Having not received
导游人员进行导游活动，( )。
A．可以私自承揽 B．可以直接承揽导游业务C．必须经旅行社委派 D．必须经旅游行政管理部门批准
