  We employ one-particle-exchange method to study D-->PV decays in D-->K \rho,
\pi K*, \pi \rho processes. Taking into account a strong phase and considering
nonfactorizable effect, we can get good results consistent with the
experimental data. Nonfactorizable effect is not always large, but in some
cases, the nonfactorizable effect is nececcesary to accommodate the
experimental data. Strong phase is approximately SU(3) flavour symmetric.
