“No student,” the headteacher stressed, “_______ go out of the school after ten o’clock at night without my permission.”

A．must

B．will

C．shall

D．may

对逐年收益不等，长期方案，多方案进行比较时，应优先采用( )。

A．静态评价指标
B．动态评价指标
C．现金流评价指标
D．效率优先的评价指标