进行人群高血压普查时应选择的疾病频率测量指标是（）
A.发病率
B.发病专率
C.罹患率
D.时点患病率
E.期间患病率
参考答案：D
A．磁感线是磁场中实际存在的曲线
B．指南针指南北是因为地球周围存在磁场
C．地磁的南极在地理的南极附近
D．只要导体在磁场中运动，就能产生感应电流
A warm thought suddenly ____ to me ____ I might use the pocket money to buy some
flowers for my mother's birthday.[ ]
A. occurred, if
B. crossed, when
C. came, that
D. struck, that
