The plots of lobW_i vs. [L] show the following characteristics: (1) if i=1, it will be a monotonously rising parabola without a minimum; (2) if 1N, it will be a parabola with a minimum; (3) if i=N, it will be a monotonously decreasing parabola without a minimum. So we can determine the maximum ligand number N of complexes in solution with the aid of these characteristics.