范围管理在工程项目策划与决策阶段的主要内容不包括( )。
A．投资机会研究
B．初步设计
C．预可行性研究
D．可行性研究
参考答案：B
(74) systems perform basic tasks, such as recognizing input from the keyboard, sending output to the display screen, keeping track of files and (75) on the disk, and controlling peripheral devices such as disk drives and printers.
A．Operation
B．Operator
C．Operating
D．Operate
