Four boys in water are hanging on to the concrete ledge.
the boys are sitting in a chair
The boys can't sit in a chair and be in the water at the same time.
exists e1 s1 x1 x2 x3.(n_ledge(x3) & a_concrete(s1) & Theme(s1,x3) & r_on(e1) & to(e1,x3) & Actor(e1,x1) & v_hang(e1) & in(x1,x2) & n_water(x2) & n_boy(x1) & card_eq_4(x1))
exists e1 x1 x2.(n_boy(x1) & in(e1,x2) & n_chair(x2) & Actor(e1,x1) & v_sit(e1))