监控系统对被监控设备的各种事件的响应速度的性能指标量为（）。
A.5S
B.10S
C.15S
参考答案：B
下列有关合同履行中行使代位权的说法，正确的是( )。
A．债权人必须以债务人的名义行使代位权B．债权人代位权的行使必须取得债务人的同意C．代位权行使的费用由债权人自行承担D．债权人代位权的行使必须通过诉讼程序，且范围以债权为限
The scientists approached the pandas quietly and watched them. The underlined part means ____. [ ]
A. left behind
B. ran quickly to
C. went off
D. came near to
