  As previously shown BRST singlets |s> in a BRST quantization of general gauge
theories on inner product spaces may be represented in the form |s>=e^{[Q,
\psi]} |\phi> where |\phi> is either a trivially BRST invariant state which
only depends on the matter variables, or a solution of a Dirac quantization.
\psi is a corresponding fermionic gauge fixing operator. In this paper it is
shown that the time evolution is determined by the singlet states of the
corresponding reparametrization invariant theory. The general case when the
constraints and Hamiltonians may have explicit time dependence is treated.
