A man walks though an arch.
A man walks under an arbor.
man walks though an arch simply means man walks under an arbor
exists e1 x1 x2 x3.(a_topic(x1) & though(x1,x3) & n_arch(x3) & Actor(e1,x2) & v_walk(e1) & (x1 = x2) & n_man(x1))
exists e1 x1 x2.(under(e1,x2) & n_arbor(x2) & Actor(e1,x1) & v_walk(e1) & n_man(x1))