Young adults are playing musical instruments.
These are all great composers
Young adults are usually not all great composers because musical composition is a skill that requires a lot of years of experience.
exists e1 s1 s2 x1 x2.(Theme(e1,x2) & Actor(e1,x1) & v_play(e1) & n_instrument(x2) & a_musical(s2) & Theme(s2,x2) & n_adult(x1) & a_young(s1) & Theme(s1,x1))
exists p1 x1.(n_thing(x1) & all s1 x2.((n_composer(x2) & a_great(s1) & Theme(s1,x2)) -> (x1 = x2)))