A man is loaded on to a train in a wheelchair.
A person is seen smiling helping another man onto a train.
A man in a wheel chair may not necessarily have been loaded by a person smiling and helping him.  No one may have seen this happen.
exists e1 x1 x2 x3.(r_on(e1) & to(e1,x2) & in(x2,x3) & n_wheelchair(x3) & n_train(x2) & Theme(e1,x1) & v_load(e1) & n_man(x1))
exists e1 p1 x1 x2.(n_man(x2) & exists e2 p2.(exists e3 x3 x4.(onto(e3,x4) & n_train(x4) & Theme(e3,x3) & Actor(e3,x1) & v_help(e3) & n_man(x3) & -(x3 = x2)) & Topic(e2,p2) & Actor(e2,x1) & v_smile(e2)) & Recipient(e1,p1) & Topic(e1,x1) & v_see(e1) & n_person(x1))