sound velocity的用法和樣例：
例句
- Mach two equals twice the speed of sound.
二馬赫相當於聲速的二倍。 - "A sweet temper" is a figurative expression, but "sweet coffee" is not.
"甜蜜的性情"是個比喻的說法，而"甜咖啡"則不是。 - The plane is flying at the velocity of sound.
飛機以音速飛行。 - As the velocity in the nozzle throat is sonic, the effect must be transmitted upstream through the boundary layer.
當噴管喉部達到音速時，這種影響一定是通過附面層向上傳播而引起的。
