A small boy climbing a backyard play set.
The boy is climbing on his knees.
One can climb on his feet also, not only on the knees.
exists e1 e2 s1 x1 x2 x3 x4.(Theme(e2,x1) & v_set(e2) & Theme(e1,x3) & Actor(e1,x2) & v_climb(e1) & n_play(x3) & of(x3,x4) & n_backyard(x4) & (x1 = x2) & n_boy(x1) & a_small(s1) & Theme(s1,x1))
exists e1 x1 x2.(n_knee(x2) & of(x2,x1) & n_male(x1) & n_boy(x1) & on(e1,x2) & Actor(e1,x1) & v_climb(e1))