He was arrested after being kept under constant surveillance.

在被连续监视了一段时间后，他被逮捕了。

Police swooped on the home after a two-week surveillance operation.

在两周的监视行动之后，警方突击搜查了那栋房子。

Police keep track of the kidnapper using electronic surveillance equipment.

警方利用电子监视设备跟踪绑架者。