surveillance
n. 监视，监察
例句
He was arrested after being kept under constant surveillance.
他在被连续监视之后给逮捕了。
《柯林斯英汉双解大词典》
The police are keeping the suspects under constant surveillance.
警方正对嫌疑人实施不间断监视。
《牛津词典》
Police swooped on the home after a two-week surveillance operation.
警方经过两周的监视行动后突击搜查了该住宅。
