⑨lack v．缺少，缺乏

　　⑩too ... to ... 太......而不能......

　　⑪dance to 伴着......跳舞(to用作介词)

　　⑫spring up 突然兴起，迅速出现

　　⑬trumpet/'trʌmpIt/n.小号；喇叭

　　⑭liberty/'lIbətI/n.自由

　　⑮he brought to his music 是一个定语从句，修饰liberty，在从句中作宾语的关系代词which/that 省略了。

　　⑯while 引导时间状语从句，while 表示"正当......时候"。

　　从蓝调音乐到流行乐

　　早期爵士乐

　　今天我将简要地回顾一下西方音乐是如何从蓝调音乐发展到流行乐的。现代流行音乐起源于奴隶制时期美国黑人的民歌。在19世纪晚期，黑人音乐家们根据这些民歌创造了一种被称作蓝调音乐(又译布鲁斯)的音乐形式，因为这种音乐有忧伤的趋势。尽管蓝调音乐非常受欢迎，但作为一种音乐形式，它缺少变化，而且太伤感、节奏太慢，不适合跳舞时伴奏。于是，从蓝调音乐中发展出一种节奏更轻快、更活泼的音乐形式，叫作爵士乐。

　　黑人小号手及歌手路易斯·阿姆斯特朗是爵士乐的创始人之一。与其他大部分按照写好的乐谱演奏的音乐家不同，他会在演奏时即兴改变原来的曲子，以反映他演奏时的心情。其他的乐手开始模仿他的风格以及他赋予音乐的自由。在演奏时可以即兴改编音乐成为爵士乐的主要特征之一。

　　From R & B to rock and roll⑰

From the early 1930s to the early 1950s, traditional jazz went into a gradual⑱ decline⑲， and was replaced by a new musical trend⑳ known as rhythm\s\up1(21(21) and blues, or R & B. R & B was then - and now - often thought of as a form of African­American music. It combined the fast pace of many kinds of jazz with the older blues sound. During the early 1950s, one particular style of R & B became popular - rock and roll. One of the first rock and roll musicians was Big Joe Turner. He was a black American singer who had started out performing jazz in the 1920s, and then turned to R & B in the 1940s. In 1954, he recorded one of the very first rock and roll songs, 'Shake