人体初次接受某种疫苗全程足量的预防接种，称为（）
A.基础免疫
B.加强免疫
C.自动免疫
D.被动免疫
E.应急接种
参考答案：A
Jane would never have gone to the party ____ that Mary would come to see her. [ ]
A. has she known
B. had she known
C. if she knows
D. if she has known
道氏理论认为( )是最重要的价格，并利用该价格计算平均价格指数。( )
A．开盘价 B．收盘价 C．最高价 D．最低价
