  In this paper, we will consider the problem that how far from Hunt's
hypothesis (H) to symmetrization for a general 1-dimensional diffusion. A
characterization of (H) involving the classification of points for this
diffusion will be first obtained. Then the main result shows that such a
process is symmetrizable, if and only if (H) holds and a certain family of
asymmetric shunt points is empty. Furthermore, we will also derive the
representation of associated Dirichlet forms of general 1-dimensional
diffusions under symmetry.
