把一个直径为10厘米粗的实心钢管锯断1次要用5分钟，锯断3次需要（ ）分钟。
15
You can imagine what great trouble they have ______ the problem ______. [ ]
A. to solve; being talked about
B. solving; discussing
C. to solve; to talk about
D. solving; being discussed
已知8253的Cho用作计数器，口地址为40H，计数频率为2MHz。控制字寄存器口 地址为43H，计数器回0时输出信号用作中断请求信号，执行下列程序段后，发出中断请求信号的周期是______。 MOV AL，36H OUT 43H，AL MOVAL，OFFH OUT 40H，AL OUT 40H，AL
