One of the soldiers began to turn, alerted by some small sense.

He had no wish to alert them to his own presence by any touch of mind.

He broke off, alerted by some change in the night's sounds.

Alice looked up, alerted by the change in his tone.

But always the first thing was to state the problem to one's self, to alert the senses by this means.

And now members of staff were closing in, alerted by her yell.

Before he could answer, Nelson appeared, alerted by a familiar voice.

From the corridor outside someone shouted, alerted by the shot.

Alerted by some instinct, already I knew something strange was happening.

He looked up, alerted by something in her voice.