A shirtless skateboarder.
A skateboarder is cooking.
One is just a skateboarder, and one is a skateboarder cooking. One does not usually cook shirtless.
exists s1 x1.(a_topic(x1) & n_skateboarder(x1) & a_shirtless(s1) & Theme(s1,x1))
exists s1 x1.(Theme(s1,x1) & a_cooking(s1) & n_skateboarder(x1))