The biker is riding through the woods.
A man is biking through the woods.
Not every biker is a man.
exists e1 x1 x2.(n_wood(x2) & n_biker(x1) & through(e1,x2) & Actor(e1,x1) & v_ride(e1))
exists e1 x1 x2.(n_wood(x2) & through(e1,x2) & Actor(e1,x1) & v_bike(e1) & n_man(x1))