A man is sleeping on his front doorstep.
The man slept on the doorstep.
A man who slept is also a man who was sleeping.
exists e1 s1 x1 x2.(on(e1,x2) & n_doorstep(x2) & a_front(s1) & Theme(s1,x2) & of(x2,x1) & n_male(x1) & Actor(e1,x1) & v_sleep(e1) & n_man(x1))
exists e1 x1 x2.(n_doorstep(x2) & n_man(x1) & on(e1,x2) & Actor(e1,x1) & v_sleep(e1))