Two cyclists traverse a green terrain.
The cyclists are on a desert.
The desert is not green.  The cyclists cannot be in a desert and on green terrain.
exists e1 s1 x1 x2.(Theme(e1,x2) & Actor(e1,x1) & v_traverse(e1) & n_terrain(x2) & a_green(s1) & Theme(s1,x2) & n_cyclist(x1) & card_eq_2(x1))
exists p1 x1.(n_cyclist(x1) & exists x2.(on(x1,x2) & n_desert(x2)))