A guard sits near the ticket booth, monitoring the comings and goings through the portal, making sure that too many people don't do it at the same time and alarm the Muggles.

一个守卫坐在售票亭旁，监视着(穿越墙柱)过来的入口，确认同一时刻不能有太多的人通过以免引起麻瓜的警觉。

youdao

But Rod Booth, who chairs the Independent Monitoring Board, denied there were full scale riots.

BBC: Morton Hall Immigration Centre

Enthusiasts are welcome to visit the booth to experience for themselves the convenient, powerful, and complete monitoring functionality you have when overclocking with Afterburner using an Android phone or tablet PC.

ENGADGET: MSI's Afterburner Android app makes GPU overclocking as easy as Facebooking