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.

Keith Richards ( born 18 December 1943 ) is an English guitarist best known as a founder member of the Rolling Stones .
Keith Richards ( born 18 December 1943 ) is an English musician , singer , and songwriter , best known as the co-founder , guitarist , secondary vocalist , and co-principal songwriter of the Rolling Stones .