A grammar question.

zasdzcc

Willie Dixon's upbeat blues compositions helped usher in  the Chicago blues sound of the 1950s and became standard numbers  for the many young rock groups that were  trying to achieve popularity during the 1960s. 请问这句话是什么意思?用了哪些用法？ Thanks.

gre3333

有几个词意思搞清楚，句子就容易理解了。

upbeat n. [音]弱拍

usher  vt.（常与in连用）宣告，展示