It also focuses on the two key elements which influenced the emergence of the classic Hollywood studio system: the advent of sound and the business ideal of vertical integration.
它还关注了经典好莱坞工作室系统出现的两个关键影响因素：声音的出现和纵向一体化的商业理念。
2
On the other hand, many think it's the basic physical properties of sound that hold the key to perceiving sounds as appealing or jarring.
另一方面，许多人认为声音的基本的物理属性，是决定听者感知为和谐或不和谐的关键。
3
Understanding the mechanism is the key to making a sound selection.