当物体在外力作用下越过静止的临界状态，沿另一物体表面发生相对运动时的摩擦叫动摩擦。
参考答案：对
If flotation costs are treated correctly in calculating the net present value of a project that will begin in the current period, the flotation costs are most likely:（）
A. reflected in the discount rate used for the project.
B. included in the initial outlay.
C. to reduce NPV less if a high discount rate is used for the project.
某工程施工网络计划如下图所示。当监理工程师因设计图纸提交时间延误而令工作D的持续时间由4d延长到8d时，承包商可索赔的工期为（）d。
A．4
B．3
C．1
D．0
