He rapped the door once with the tip of his shoe, hard.

She got up, rapped once on the glass door, then let herself through.

He rapped once, sharply, on the carved panel, then opened it.

The guard stepped to the door and rapped once.

She rapped once, opened it, stepped back, and ushered me in.

I rapped once, twice, with the ash wand of my office- No answer.

He walked to the inner office door, rapped once, and pushed it open in the same motion.

He rapped once, then bowed to me, whirled, and left without waiting for an answer.

Kevin rapped once on the table with a small block of wood.

Modesty rapped once with her knuckles on the door, opened it, and walked in.