n.速度；迅速；速率
The velocity of sound in water is more than four times that in air. 聲音在水中的速度是在空氣中的速度的4倍多。
Gazelles can move with astonishing velocity. 羚羊跑起來(lái)速度驚人。
The velocity of light is about 186,000 miles per second. 光速大約是每秒十八萬(wàn)六千英里。
