Two musicians are on a stage, one plays the bass guitar.
there are two musicians, one plays the bass
one plays the bass guitar also means he plays the bass.
exists p1 x1 x4 x5.(n_guitar(x4) & of(x4,x5) & n_bass(x5) & exists p2 x2.(on(x1,x2) & exists e1 x3.(Theme(e1,x4) & Actor(e1,x3) & v_play(e1) & n_thing(x3) & card_eq_1(x3)) & that(x2,p2) & n_stage(x2)) & n_musician(x1) & card_eq_2(x1))
exists p1 x1 x4.(n_bass(x4) & exists p2 x2.((x1 = x2) & exists e1 x3.(Theme(e1,x4) & Actor(e1,x3) & v_play(e1) & n_thing(x3) & card_eq_1(x3)) & that(x2,p2) & n_musician(x2) & card_eq_2(x2)))