监控中心内应设置等电位连接网络，防止地线之间有电位差。
参考答案：对
对于任意实数x，多项式x2-6x+10的值是一个（ ）
A．负数
B．非正数
C．正数
D．无法确定正负的数
Since the epidemic appeared last winter, it ______ about a hundred lives. [ ]
A. takes
B. took
C. has taken
D. will take
