So how do these musicians generate two hours of music with no music in front of them?

那这些音乐家是如何持续演出两个小时的呢,在没有乐谱的情况下

耶鲁公开课 - 聆听音乐课程节选

let's say within 72 hours, my music is up on i-Tunes, you know, Amazon,

比如说，72个小时之内，我的音乐就在i-Tunes上了，你知道，还有亚马逊上，

请听听我的歌 - SpeakingMax英语口语达人

He will sometimes play the Shubert Theater there and they'll have two hours of spectacular jazz, but what you won't see, again is any sort of music in front of them.

他有时候会在舒伯特音乐厅演出,两个小时精彩绝伦的爵士乐表演,但同样,你不会看到,任何曲谱摆在他们面前

耶鲁公开课 - 聆听音乐课程节选