A man demonstrates his product.
A man is showing a product.
Demonstrates a products means the same thing as is showing a product.
exists e1 x1 x2.(Theme(e1,x2) & Actor(e1,x1) & v_demonstrate(e1) & n_product(x2) & of(x2,x1) & n_male(x1) & n_man(x1))
exists e1 x1 x2.(Theme(e1,x2) & Actor(e1,x1) & v_show(e1) & n_product(x2) & n_man(x1))