Although 19,000 cubic feet of hydrogen may sound like a lot, it really isn't.

He turned his head as a foot sounded on the wall's stone.

At that moment, running feet sounded on the ramp from the ground floor.

The running feet sounded too close around the corner.

I said, "Ten feet sounds like a hell of a lot."

A foot sounded behind him, and he turned quickly from the altar.

He didn't get an answer, for running feet sounded in the outside hall.

"Seventeen feet off the ground doesn't sound like much until you're up here looking down."

Hasty feet sounded on the stairs beyond the open door.

But the feet did not sound as if they were following her.