给水系统中所用管材,从材质上可划分为金属类管和非金属类管两大类,属于金属的管材是()。
A.钢筋混凝土管
B、钢筒混凝土管
C、衬塑钢管
D、玻璃钢管
参考答案:C
For a project with conventional cash flows and a negative net present value, the profitability index is most likely:()
A. less than one.
B. equal to one.
C. more than one.
地温正常区与地温异常区的界定值是()
A.2.7℃/100m
B.2.8℃/100m
C.2.9℃/100m
D.3℃/100m