机械如在110kV高压线下进行工作或通过时，其最高点与高压线之间的最小垂直距离不得小于( )m。
A．2 B．3C．4 D．5
参考答案：C
An analyst does research about capital budgeting. If the introduction of a new product is expected to decrease sales of an existing product, which of the following is most accurate to describe the change in the existing product's cash flows（）
A. Externality.
B. Sunk cost.
C. Incremental cash flow.
下面不是硬件负载均衡的是（）
A.LVS
B.F5
C.Netsclar
D.Athelon
