The sun was setting when the boy's heart sounded a danger signal.
"It and the other danger signals were the first I was taught."
Dead wood must carry a special danger signal for them.
But danger signals, they caution, are there just the same.
He didn't press; her voice had danger signals in it.
Of course, he failed to listen to the danger signal.
He'd known Erik for the better part of eight months now, and he knew the danger signals.
At the first danger signal his wife had ordered the maid from the room.
All it has to do is keep sending a danger signal to the computers that control them.
It certainly is the most significant danger signal that I have yet seen.