1. Ask Ss to discuss the important and difficult language points.
(1) The words of early blues songs often consisted of a single line repeated two or three times before changing. 早期的蓝调歌曲通常包含一句要反复唱两三遍才换的歌词。
consist of无被动态，类似用法的词组还有： belong to, take place, happen, come true, come out, break out, etc.
