The biker is riding down a grassy mountainside.
A biker was in the desert.
A grassy mountainside is not located in the desert.
exists e1 s1 s2 x1 x2.(n_biker(x1) & a_down(s2) & Manner(e1,s2) & Theme(e1,x2) & Actor(e1,x1) & v_ride(e1) & n_mountainside(x2) & a_grassy(s1) & Theme(s1,x2))
exists p1 x1 x2.(n_desert(x2) & in(x1,x2) & n_biker(x1))