His efforts to raise money for his program were ________ because no one showed any intention to take

a cent out of their pockets.[ ]

A．in place  

B．in sight

C．in effect  

D．in vain

安全稳定控制系统中，采用模拟式远方传送命令信息设备来传送直跳式(无就地启动判据)命令，其传输时间要求不大于( )。

A．20ms；
B．25ms；
C．30ms；
D．40ms。