The man sits with his dog on a bench in a park.
A man sits with his dog in the park at night.
A man can sit with his dog in a park at any time of day so it is not always at night.
exists e1 x1 x2 x3 x4.(n_dog(x2) & of(x2,x1) & n_male(x1) & n_man(x1) & in(e1,x4) & n_park(x4) & on(e1,x3) & n_bench(x3) & with(e1,x2) & Actor(e1,x1) & v_sit(e1))
exists e1 x1 x2 x3 x4.(n_park(x3) & at(e1,x4) & n_night(x4) & in(e1,x3) & with(e1,x2) & n_dog(x2) & of(x2,x1) & n_male(x1) & Actor(e1,x1) & v_sit(e1) & n_man(x1))