A man with a brown shirt sits in an inter tube.
A man is floating down a river on an inter tube
Just because someone is on an inter tube does not mean they floating down a river.
exists e1 s1 x1 x2 x3 x4.(in(e1,x3) & n_tube(x3) & of(x3,x4) & n_inter(x4) & Actor(e1,x1) & v_sit(e1) & with(x1,x2) & n_shirt(x2) & a_brown(s1) & Theme(s1,x2) & n_man(x1))
exists e1 s1 x1 x2 x3 x4.(on(e1,x3) & n_tube(x3) & of(x3,x4) & n_inter(x4) & a_down(s1) & Manner(e1,s1) & Theme(e1,x2) & Actor(e1,x1) & v_float(e1) & n_river(x2) & n_man(x1))