中低压玻璃钢管道O型圈密封槽的台阶及端面不应有（），必须粘合一体。
参考答案：分层
痴呆常见虚证包括（）
A.心胆气虚证
B.髓海不足证
C.心肾脾虚证
D.脾肾两虚证
E.心气不足证
PDM includes four types of dependencies or precedence relationships:（）.The completion ofthe successor activity depends upon the initiation of the predecessor activity.
A.Finish-to-Start
B.Finish-to-Finish
C.Start-to-Start
D.Start-to-Finish
