“营销”主要包括策划、销售、客户关系维护等三层含义。
参考答案：对
John ______ in his room when he heard screaming.
A．is studying
B．studied
C．was studying
D．has studied
肌内注射的疫苗有（）
A.乙肝疫苗
B.百白破疫苗
C.麻腮风疫苗
D.乙脑疫苗
E.甲肝减毒活疫苗
F.流脑疫苗
