[en] Typical nonleptonic weak decays of strange and charm mesons are studied from the approach in which dynamical features of hadrons are dealt with in earnest. The amplitudes are always cast into the form M ≅ M_ETC + M_S by using a hard PS-meson extrapolation. M_S, which can then be regarded as the Born term, is described by the sum of pole amplitudes involving the contributions from not only the ordinary {QQ-bar} but also the exotic [QQ][Q-barQ-bar] and (QQ)(Q-barQ-bar) mesons and a glue-ball. In particular, the persistent puzzle of the ratio, Γ(D⁰ → K⁺K^-)/Γ(D⁰ → π⁺π^-) ≅ 2-5, can be solved. Simultaneously, the contribution of the (QQ)(Q-barQ-bar) mesons explains why the violation of the |ΔI| = 1/2 rule is small in the K → ππ decays, while its charm counterpart is violated strongly. (author)