Four people sit on a park bench while one plays guitar.
A man is playing the piano for his friends.
A person cannot play both the piano and the guitar.
exists e1 p1 x1 x2 x3.(exists e2 x4 x5.(Theme(e2,x5) & Actor(e2,x4) & v_play(e2) & n_guitar(x5) & n_thing(x4) & card_eq_1(x4)) & while(e1,p1) & on(e1,x2) & n_bench(x2) & of(x2,x3) & n_park(x3) & Actor(e1,x1) & v_sit(e1) & n_people(x1) & card_eq_4(x1))
exists e1 x1 x2 x3.(n_friend(x3) & of(x3,x2) & n_male(x2) & n_piano(x2) & for(e1,x3) & Theme(e1,x2) & Actor(e1,x1) & v_play(e1) & n_man(x1))