为了提高活塞环的使用寿命，减少磨损，一般对（）的工作表面进行镀铬。
A．油环
B．第一道气环
C．最下一道气环
参考答案：B
— I hear Alice was badly injured in the accident and sent to hospital.
— _______, we should go and see her immediately. [ ]
A. If so
B. When necessary
C. On condition that
D. Believe it or not
当8088/8086的S4=0，S3=1时，表示当前正使用( )段寄存器。
A．ES
B．CS
C．DS
D．SS
