监视

We are still under watch.

He was under close observation by the police.

Radar monitors the plane's takeoff.

keep a sharp lookout; keep a close watch (on); keep under observation

keep the suspects under round-the-clock surveillance

electronic surveillance

keep watch in secret

monitoring system

surveillance television

supervisory program

be/come under observation

tighten/remove surveillance (on)

place the enemy under surveillance

monitor the disease