[en] We develop an analytic model of intermittent, three-dimensional, strong, reduced magnetohydrodynamic (RMHD) turbulence with zero cross helicity. We take the fluctuation amplitudes to have a log-Poisson distribution and incorporate into the model a new phenomenology of scale-dependent dynamic alignment between the Elsässer variables ${\mathit{z}}^{\pm <!--\; ??\; -->}$. We find that the structure function $⟨<!--\; ???\; -->|\mathrm{\Delta <!--\; ??\; -->}{\mathit{z}}_{\mathrm{\lambda <!--\; ??\; -->}}^{\pm <!--\; ??\; -->}{|}^n⟩<!--\; ???\; -->$ scales as ${\mathrm{\lambda <!--\; ??\; -->}}^{1-<!--\; ???\; -->{\mathrm{\beta <!--\; ??\; -->}}^n}$, where $\mathrm{\Delta <!--\; ??\; -->}{\mathit{z}}_{\mathrm{\lambda <!--\; ??\; -->}}^{\pm <!--\; ??\; -->}$ is the variation in ${\mathit{z}}^{\pm <!--\; ??\; -->}$ across a distance $\mathrm{\lambda <!--\; ??\; -->}$ perpendicular to the magnetic field. We calculate the value of β to be ≃ 0.69 based on our assumption that the most intense coherent structures are two-dimensional with a volume filling factor $\propto <!--\; ???\; -->\mathrm{\lambda <!--\; ??\; -->}$. Two consequences of this structure-function scaling are that the total-energy power spectrum is $\propto <!--\; ???\; -->k_{\perp <!--\; ???\; -->}^{-<!--\; ???\; -->1.52}$ and the kurtosis of the fluctuations is $\propto <!--\; ???\; -->{\mathrm{\lambda <!--\; ??\; -->}}^{-<!--\; ???\; -->0.27}$. Our model resolves the problem that alignment angles defined in different ways exhibit different scalings. Specifically, we find that the energy-weighted average angle between the velocity and magnetic-field fluctuations is $\propto <!--\; ???\; -->{\mathrm{\lambda <!--\; ??\; -->}}^{0.21}$, the energy-weighted average angle between $\mathrm{\Delta <!--\; ??\; -->}{\mathit{z}}^{+}$ and $\mathrm{\Delta <!--\; ??\; -->}{\mathit{z}}^{-<!--\; ???\; -->}$ is $\propto <!--\; ???\; -->{\mathrm{\lambda <!--\; ??\; -->}}^{0.10}$, and the average angle between $\mathrm{\Delta <!--\; ??\; -->}{\mathit{z}}^{+}$ and $\mathrm{\Delta <!--\; ??\; -->}{\mathit{z}}^{-<!--\; ???\; -->}$ without energy weighting is $\propto <!--\; ???\; -->{[\mathrm{l}\mathrm{n}(L/\mathrm{\lambda <!--\; ??\; -->})]}^{-<!--\; ???\; -->1/2}$ when $L/\mathrm{\lambda <!--\; ??\; -->}\gg <!--\; ???\; -->1$, where L is the outer scale. We also carry out a direct numerical simulation of RMHD turbulence. The scalings in our model are similar to the scalings in this simulation as well as the structure-function scalings observed in the slow solar wind.