Sentence:Athos, Porthos and Aramis were soldiers in the very prestigious [e1]regiment[/e1] of The King's [e2]musketeers[/e2] - something like King's Guard- which main arm, in the battlefield was the musket, a very heavy gun that needed to be held on a fork.
 e1: regiment. 
 e2 : musketeers.
Answer: Member-Collection(e2,e1)