A drum makes sound when its skin shakes.
鼓面一震动，就发出咚咚声。
The shaking pushes the air around it.
这震动，推着周围的空气往前走。
Low sound waves travel very far.
低频的声波呀，能传得特别远。
That is why drums are heard miles away.
所以几里地外，都能听见鼓声。
Long ago, people sent news by drums.
古时候，人们靠鼓声来传消息。
Big drums still wake up a whole crowd today.
现在大鼓一响，全场都跟着精神起来。
