决策的主要类型包括():①紧急情况下的决策;②一般情况下的决策;③随意情况下的决策;④日常工作中的决策。 A.
①②③ B.
①②④ C.
②③④ D.
①③④

多项选择题设A和B都是无限集，B⊆A,问A−B是否（）？

单项选择题The PR specialists pay close attention to government policy changes, and try to help local governments with projects of public management. This PR activity is called ____. A、Product publicity B、Press relations C、Public affairs D、Government relation