Towards Precise Determinations of the CKM Matrix without Hadronic Uncertainties

We illustrate how the measurements of the CP asymmetries in $B_{d,s}^0$-decays together with a measurement of $Br(K_L\to \pi^\circ\nu\bar\nu)$or$Br(K^+\to \pi^+\nu\bar\nu)$andtheknownvalueof$\mid V_{us}\mid $ can determine all elements of the Cabibbo-Kobayashi-Maskawa matrix essentially without any hadronic uncertainties. An analysis using the ratio $x_d\mathrm{/}{x}_s$ of $B_d-{\bar{B}}_d$ to $B_s-{\bar{B}}_s$ mixings is also presented.