In this task, we ask you to elaborate the sentence without changing its general meaning. You can do so by explaining further the input sentence, using more precise wording, adding qualifiers and auxiliary information etc.
One example: The Inheritance Cycle is a series of fantasy books written by Christopher Paolini.
Solution is here: The Inheritance Cycle is a tetralogy of young adult high fantasy novels written by American author Christopher Paolini.
Explanation: The output sentence elaborates on the input sentence without changing its general meaning e.g. "tetralogy of young adult high fantasy novels".

Now, solve this: No year can be cited as the origin , because the style evolved over a long period .
Solution:
No specific year can be cited as the origin of the blues , largely because the style evolved over a long period and existed in approaching its modern form before the term " blues " was introduced and before the style was thoroughly documented .