下列哪些属于局域网软件系统的有机组成部分（）
A、服务器
B、客户机
C、网络通信协议
D、操作系统
参考答案：C, D
—We should adopt ________methods to deal with some incidents. You know，anything could occur in that situation.
—I got it. Thank you for reminding me.
A．flexible
B．typical
C．positive
D．concrete
仰卧起坐练习主要锻炼()
A．腹肌
B．腰背肌
C．腰大肌
D．骨盆肌
E．背部柔韧性
