The art or operation of regulating occurrence, pace, or coordination to achieve the most desirable effects, as in music, the theater, athletics, or mechanics.
时机掌握掌握发生、步伐或协调以达到最理想效果的艺术或操作，如在音乐、戏剧、运动或机构中
A device, such as a ruler, tab, or bar, that serves as an indicator or acts to regulate a motion or operation.
