  The averaging principle is established for the slow component and the fast
component being two dimensional stochastic Navier-Stokes equations and
stochastic reaction-diffusion equations, respectively. The classical
Khasminskii approach based on time discretization is used for the proof of the
slow component strong convergence to the solution of the corresponding averaged
equation under some suitable conditions. Meanwhile, some powerful techniques
are used to overcome the difficulties caused by the nonlinear term and to
release the regularity of the initial value.
