n.a person employed to watch for something to happen
同义词：lookoutlookout mansentinelwatchspotterscoutpicket
Sentries
Space sentries
Secret sentries in space
Sentries and Sleepers in Sensor Networks
Sentries and sleepers in sensor networks
Twenty-first century sentries
Sentries at the gate: chemokines and the blood-brain barrier
Toll-like receptors--sentries in the B-cell response.
Protease-activated receptors: sentries for inflammation?
Psychological Intervention on Mental Health of Sentries in Remote Post
