Two men performing a song, one singing, the other playing an instrument.
the men are singers
Not all people that play an instrument are singers.
exists e2 e1 x1 x2 x3 x4 x5.(n_other(x4) & Theme(e2,x5) & Actor(e2,x4) & v_play(e2) & n_instrument(x5) & rel(e1,x3) & n_singing(x3) & card_eq_1(x3) & Theme(e1,x2) & Actor(e1,x1) & v_perform(e1) & n_song(x2) & n_man(x1) & card_eq_2(x1))
exists p1 x1.(n_man(x1) & exists x2.((x1 = x2) & n_singer(x2)))