The man stumbled once, almost losing his balance, and caught himself against the wall with one hand.

He once stumbled upon a research document left behind by one of his ancestors.

The surgeon walked around to the left side of the table, stumbling once.

She stumbled once, but his strong grip kept her from falling.

It stumbled once and went back down, but then tried to rise again.

He stumbled once on the steps, but caught himself in time.

Run up and down a few times, making sure to stumble at least once.

He made his way in the dark, stumbling once or twice.

"Even you might stumble on a smart idea once in a while."

He stumbled once, forced himself upright again, and kept moving.