A piano has black and white keys.
钢琴上有黑键，也有白键。
Most pianos have 88 keys in total.
大多数钢琴，一共有88个键。
Long ago, pianos had fewer keys.
很早以前，钢琴的键比现在少。
Musicians wanted more high and low sounds.
音乐家想要更高、更低的音。
So makers added more keys over time.
于是厂家一点点加上了更多键。
Eighty-eight keys cover almost every note.
88个键，几乎够用了。
Too many more would make it hard to play.
再加多了，反而不好弹了。
