数值资料的频数分布中，高峰位于中央，图形的左右对称的分布是（）
A.正态分布
B.正偏态分布
C.负偏态分布
D.二项分布
E.泊松分布
参考答案：A
ACEI的主要不良反应是（）
A.干咳
B.尿量增多
C.头痛
D.面色潮红
E.心动过缓
A work breakdown structure (WBS) is a tool used to define and group a project's discrete work elements in a way that helps organize and define the total work scope of the project. A WBS is most useful for ______.
A．identifying individual tasks for a projectB．scheduling the start of tasksC．scheduling the end of tasksD．determining potential delays
