Two men perform a song together on stage.
The two men are skating.
two men cannot perform a song or skating at the same time
exists e1 s1 x1 x2 x3.(on(e1,x3) & n_stage(x3) & a_together(s1) & Manner(e1,s1) & Theme(e1,x2) & Actor(e1,x1) & v_perform(e1) & n_song(x2) & n_man(x1) & card_eq_2(x1))
exists e1 x1.(n_man(x1) & card_eq_2(x1) & Actor(e1,x1) & v_skate(e1))