A boy runs across the desert.
Timmy ran in the desert.
Timmy is is the boy that ran across the desert.
exists e1 x1 x2.(n_desert(x2) & across(e1,x2) & Actor(e1,x1) & v_run(e1) & n_boy(x1))
exists e1 x1 x2.(n_desert(x2) & ne_per_timmy(x1) & in(e1,x2) & Actor(e1,x1) & v_run(e1))