什么是随机误差？系统误差？粗大误差？
在Windows 95/98中不能激活开始菜单是（）。 ["用鼠标单“开始”按钮","按下Alt+Esc","按下Ctrl+Esc","按下Windows标键"]
Which statement about the Navigation Rules is TRUE?（）. ["The rules require vessels to comply with Traffic Separation Scheme regulations","The rules use the term safe speed","The Rules permit a stand-on vessel to take action prior to being in extremis","All of the above are correct"]
8051的（）引脚应至少保持2个机器周期的高电平，才能使8051复位。
取款机监控设备资料保存的天数必须是（）。 ["A.30天以上","B.60天以上","C.90以上","D.120天以上"]
专业版的移动证书密码是如何构成的？
