A small child crawling on a windowsill.
a child crawls on the windowsill
A small child is also a child. Someone who is crawling can be described as one who crawls.
exists s1 x1 x2 x3.(a_topic(x1) & on(x1,x3) & n_windowsill(x3) & n_crawling(x1) & of(x1,x2) & n_child(x2) & a_small(s1) & Theme(s1,x1))
exists e1 x1 x2.(n_windowsill(x2) & on(e1,x2) & Actor(e1,x1) & v_crawl(e1) & n_child(x1))