A man riding a dirt bike
A man is riding a dirtbike with his friend.
riding dirtbike doesn't imply with friend
exists e1 x1 x2 x3 x4.(a_topic(x1) & Theme(e1,x3) & Actor(e1,x2) & v_ride(e1) & n_bike(x3) & of(x3,x4) & n_dirt(x4) & (x1 = x2) & n_man(x1))
exists e1 x1 x2 x3.(with(e1,x3) & n_friend(x3) & of(x3,x1) & n_male(x1) & Theme(e1,x2) & Actor(e1,x1) & v_ride(e1) & n_dirtbike(x2) & n_man(x1))