A man sits alone on a bench.
The man is waiting on someone.
Just because the man is sat alone it does not necessarily mean he is waiting for someone.
exists e1 s1 x1 x2.(on(e1,x2) & n_bench(x2) & a_alone(s1) & Manner(e1,s1) & Actor(e1,x1) & v_sit(e1) & n_man(x1))
exists e1 x1 x2.(n_man(x1) & on(e1,x2) & n_person(x2) & Actor(e1,x1) & v_wait(e1))