A project manager needs to analyze the project cost to find ways to decrease costs. It would be BEST if the project manager looks at （）.

A．variable costs and fixed costs

B．fixed costs and indirect cost

C．direct costs and variable costs

D．indirect costs and direct costs

罐区机械设备试运转的第一步聚是（）。

A.无负荷试验

B.置换

C.带荷试验

D.试压