  For description of the $d, s, b$ quark mixings the Cabibbo-Kobayashi-Maskawa
matrices are used but they do not contain the time dependence. In this work the
analogous matrix is obtained for the case of three neutrino ($\nu_{e}, \nu_{\mu
}, \nu_{\tau}$) mixings (oscillations) in vacuum in the general case, when CP
violation is absent. In contrast to the quark case this matrix contains the
time dependence. The matrix for probability of neutrino transitions
(oscillations) in vacuum is also obtained. Naturally, it contains the time
dependence. The matrix which does not contain the time dependence is obtained
by using time $t$ averaging of this matrix. Elements of this matrix can be used
to describe neutrino decays.
