压力可以用绝对压力或相对压力来表示，表压通常指绝对压力。( )
参考答案：错
As part of monitoring and controlling, project performance must be monitored and measured regularly to identify variances from the plan. All the following are processes involved with controlling EXCEPT （）.
A．verify scope
B．risk monitoring and control
C．performance reporting
D．quality assurance
土壤具有缓冲作用的机理是（）
A.土壤溶液具有弱酸及其盐类组成的缓冲体系
B.土壤胶体的离子交换吸收作用
C.两性物质的作用
D.土壤微生物
