A man Rollerblades on a skate course.
The man is sitting down.
One cannot be sitting down while he is on Rollerblade's on a skate course.
exists e1 s1 x1 x2.(on(e1,x2) & n_course(x2) & a_skate(s1) & Theme(s1,x2) & Actor(e1,x1) & v_rollerblade(e1) & n_man(x1))
exists e1 s1 x1.(n_man(x1) & a_down(s1) & Manner(e1,s1) & Actor(e1,x1) & v_sit(e1))