A man in shorts on an elliptical.
A man is swimming in the pool.
On an elliptical and swimming are different actions.
exists x1 x2 x3.(a_topic(x1) & in(x1,x2) & on(x2,x3) & n_elliptical(x3) & n_shorts(x2) & n_man(x1))
exists e1 x1 x2.(n_pool(x2) & in(e1,x2) & Actor(e1,x1) & v_swim(e1) & n_man(x1))