  The generalized master equation with two times, introduced in earlier,
applies to the problem of diffusion in an time-dependent (in general
inhomogeneous) external field. We consider the case of the quasi Fokker-Planck
approximation, when the probability transition function for diffusion
(PTD-function) does not possess a long tail in coordinate space and can be
expanded as the function of instantaneous displacements. The more complicated
case of the long tails in PTD will be discussed separately.
