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
-Shall we go to the park on Sunday?
-_________.[ ]
A. I don't want to
B. I have no time
C. Sorry, but I must finish my homework first
D. Thank you
简述法律概念的功能。
