上齿轮

The teeth on the gears mesh as they turn round.

转动时齿轮的齿与齿相啮合。

The statue of General Sedgwick, cast from cannons captured by the VI Corps which he commanded during the Civil War, has rowel spurs that turn.

塞吉维克的塑像由一门战中领导的六团缴获的大炮浇铸成，周围是马刺的小齿轮。