A boy runs across the desert.
Timmy was at the desert.
Not all boys are Timmy.
exists e1 x1 x2.(n_desert(x2) & across(e1,x2) & Actor(e1,x1) & v_run(e1) & n_boy(x1))
exists p1 x1 x2.(n_desert(x2) & ne_per_timmy(x1) & at(x1,x2))