We study Khintchine's conjecture : The sequence of partial quotients in the continued fraction expansions of algebraic numbers (degree ≧ 3) is random and unbounded. Our purpose is to show that the asymptotic behavior of these partial quotients is unpredictable by proving that the gap value of recurrent dimensions is positive, or chaotic by proving that its topological entropy is positive. Here we give the following partial results : For some transcendental numbers the topological entropies  and the recurrent dimensions of the sequences of their partial quotients are zero.