Man welding large pipe section while wearing mask.
A man is playing checkers.
You cannot be welding and playing checkers at the same time.
exists e1 e2 s1 x1 x2 x3 x4 x5.(a_topic(x1) & while(e1,e2) & Theme(e2,x5) & Actor(e2,x2) & v_wear(e2) & n_mask(x5) & Theme(e1,x3) & Actor(e1,x2) & v_weld(e1) & n_section(x3) & of(x3,x4) & n_pipe(x4) & a_large(s1) & Theme(s1,x3) & (x1 = x2) & n_man(x1))
exists e1 x1 x2.(Theme(e1,x2) & Actor(e1,x1) & v_play(e1) & n_checkers(x2) & n_man(x1))