Complex sentence: This drama club originated in the basement of the Hollywood Public Library, but eventually Y.W.C.A. got involved and the group flourished, growing in size all the way up to the 175 members it contained in 1917.
Split into simpler sentences: This drama club originated in the basement of the Hollywood Public Library. Eventually the Y.W.C.A. got involved and the group flourished, growing in size all the way up to the 175 members it contained in 1917.