“监视器”造句

跑步机上有个脉搏监视器.
The treadmill has a heart rate monitor.

如果从监视器上发现任何异常,立刻通知我.
Warn me immediately if something moves on your screens.

在经纪公司为什么需要监视器 呢 ?
Why would you need a surveillance camera in a brokerage firm?