A person in a helmet rides a four-wheel vehicle in the desert.
A person is out in the desert.
A person is in the desert, riding a four-wheel vehicle.
exists e1 s1 x1 x2 x3 x4.(n_desert(x4) & Theme(e1,x3) & Actor(e1,x1) & v_ride(e1) & in(x3,x4) & n_vehicle(x3) & a_four-wheel(s1) & Theme(s1,x3) & in(x1,x2) & n_helmet(x2) & n_person(x1))
exists p1 s1 x1 x2.(n_desert(x2) & a_out(s1) & Manner(p1,s1) & in(x1,x2) & n_person(x1))