At the sound of someone approaching he escapes into the library.

At the sense, rather than the sound, of someone approaching, he turned toward the landers.

The sound of the ambulance approaches as the series ends.

The sound of dry leaves under feet, ferns by a shoulder, approached me from behind, stopped.

Footsteps and the sound of a boy's voice were approaching the hedge.

The boat was drifting down the lake, and, at the sound of another motor craft approaching, Tom looked up.

They hadn't heard the doors open, or the sound of the two men approaching.

The sound was approaching along the west bank of the river above them.

As the sound of sirens approached, Belcher told the men he had to kill himself and "can't be here".

It came nearer as the sound of the motor approached.