A bearded man is playing a banjo.
A man is an expert at the banjo
Just because a man with a beard is playing the banjo does not mean the man is an expert at the banjo, or has ever played the banjo before.
exists e1 s1 x1 x2.(Theme(e1,x2) & Actor(e1,x1) & v_play(e1) & n_banjo(x2) & n_man(x1) & a_bearded(s1) & Theme(s1,x1))
exists p1 x1 x3.(n_banjo(x3) & exists x2.((x1 = x2) & at(x2,x3) & n_expert(x2)) & n_man(x1))