实现步进电动机通电环形分配的三种常用方法是：（）（）（）
参考答案：1）采用计算机软件分配器;2）小规模集成电路搭接的硬件分配器;3）专用模块分配器
Which of the following statements about achieving proper timing in fiscal policy is FALSE（）
A. Improvements in quantitative methods have made the occurrence of recessions or expansions quite predictable.
B. There is usually a time lag between when a change in policy is needed and when the need is recognized by policy makers.
C. The time required to change tax laws and government expenditure programs can be lengthy.
语句cout＜＜setprecision(2)＜＜1024.4567；的输出结果为
A．1024.4567
B．1024
C．1024.45
D．le+003
