  In this paper, we investigate the controlled system described by
forward-backward stochastic differential equations with the control contained
in drift, diffusion and generator of BSDE. A new verification theorem is
derived within the framework of viscosity solutions without involving any
derivatives of the value functions. It is worth to pointing out that this
theorem has wider applicability than the restrictive classical verification
theorems. As a relevant problem, the optimal stochastic feedback controls for
forward-backward system are discussed as well.
