Sentries

We'll never get past those sentries.

Sami walked at night to avoid German sentries.

The two sentries were shot down, and so was a corporal who came running to see what was the matter.

The sentries stood bolt upright and stock-still.

The sentries were standing bolt upright and motionless.

In the game of Go, the stones are motionless; they remain in their positions like sentries defending the territory that they help to delimit.

The sentries are on guard.

The sentries are on guard duty.