We must be careful that the guards do not hear.

A guard sitting at the foot of the coffin heard him.

The guard on duty heard his story and then allowed them to enter.

She lowered her voice so that the guards wouldn't hear.

But the guards had not heard and she moved it again.

The guard heard the sound and came on a run.

The guard must have heard something, because he started to turn.

Then he lowered his voice so that the guards could not hear.

The guard heard this whisper and looked toward the door.

There was no sign of any struggle nor did the guards hear anything.