A man wearing a backpack is walking down the street.
A guy is walking to class.
Not every man wearing a backpack is walking to class.
exists e1 e2 s1 x1 x2 x3 x4.(n_street(x4) & a_down(s1) & Manner(e2,s1) & Theme(e2,x4) & Actor(e2,x1) & v_walk(e2) & Theme(e1,x3) & Actor(e1,x2) & v_wear(e1) & n_backpack(x3) & (x1 = x2) & n_man(x1))
exists e1 x1 x2.(to(e1,x2) & n_class(x2) & Actor(e1,x1) & v_walk(e1) & n_guy(x1))