Some men appear to be discussing something on a boat or ship.
Some men are discussing the ocean pollution on a boat.
Not all the men appear to be discussing something on a boat or ship is about ocean pollution.
exists e1 p1 x1.(Topic(e1,p1) & Actor(e1,x1) & v_appear(e1) & (exists e2 x2 x3.(Theme(e2,x2) & Actor(e2,x1) & v_discuss(e2) & on(x2,x3) & n_boat(x3) & n_thing(x2)) | exists e3 x4.(Theme(e3,x4) & Actor(e3,x1) & v_discuss(e3) & n_ship(x4))) & n_man(x1))
exists e1 x1 x2 x3 x4.(n_pollution(x2) & of(x2,x3) & n_ocean(x3) & on(e1,x4) & n_boat(x4) & Theme(e1,x2) & Actor(e1,x1) & v_discuss(e1) & n_man(x1))