A man in a yellow helmet looks up, while people on the bridge watch.
The man in a yellow helmet is in a room by himself.
The man is not by himself if people watch.
exists e1 s1 s2 x1 x2 x3 x4 x5.(n_watch(x4) & of(x4,x5) & n_bridge(x5) & on(e1,x4) & while(e1,x3) & n_people(x3) & a_up(s2) & Manner(e1,s2) & Actor(e1,x1) & v_look(e1) & in(x1,x2) & n_helmet(x2) & a_yellow(s1) & Theme(s1,x2) & n_man(x1))
exists p1 s1 x1 x2.(n_male(x1) & n_man(x1) & exists x3.(in(x1,x3) & by(x3,x1) & n_room(x3)) & in(x1,x2) & n_helmet(x2) & a_yellow(s1) & Theme(s1,x2))