A man riding on a red bicycle.
A man rides a skateboard.
You cannot ride a bicycle and a skateboard at the same time.
exists e1 s1 x1 x2 x3.(a_topic(x1) & on(e1,x3) & n_bicycle(x3) & a_red(s1) & Theme(s1,x3) & Actor(e1,x2) & v_ride(e1) & (x1 = x2) & n_man(x1))
exists e1 x1 x2.(Theme(e1,x2) & Actor(e1,x1) & v_ride(e1) & n_skateboard(x2) & n_man(x1))