A man and child posing in front of a train.
The people are by a form of transport.
A man and a child are people.
exists s1 x1 x2 x3 x4 x5.(a_topic(s1) & subset_of(x2,s1) & in(x2,x4) & of(x4,x5) & n_train(x5) & n_front(x4) & n_posing(x2) & of(x2,x3) & n_child(x3) & subset_of(x1,s1) & n_man(x1))
exists p1 x1.(n_people(x1) & exists x2 x3.(by(x1,x2) & of(x2,x3) & n_transport(x3) & n_form(x2)))