  A graphical method is developed to study the total or partial cancellation of
gauge-dependent (divergence) terms in electroweak theory. The method is used to
work out rules in the Gervais-Neveu gauge, whose triple-gauge vertex contains
three terms rather than the usual six. This and other features of the gauge
lead to an enormous saving of algebraic labor in the actual computations, as
will be illustrated explicitly in the tree process $W^++W^-\to \gamma+\gamma$.
