One man is riding his motorcycle in a desert.
No one is riding today in the desert.
Either a man is riding or no one is riding.
exists e1 x1 x2 x3.(in(e1,x2) & n_desert(x2) & Theme(e1,x3) & Actor(e1,x1) & v_ride(e1) & n_motorcycle(x3) & of(x3,x2) & n_male(x2) & n_man(x1) & card_eq_1(x1))
exists x3.(n_desert(x3) & -exists e1 x1 x2.(in(e1,x3) & Time(e1,x2) & n_today(x2) & Actor(e1,x1) & v_ride(e1) & n_one(x1)))