  We construct explicitly the $q$-vertex operators (intertwining operators) for
the level one modules $V(\Lambda_i)$ of the classical quantum affine algebras
of twisted types using interacting bosons, where $i=0, 1$ for $A_{2n-1}^{(2)}$,
$i=0$ for $D_4^{(3)}$, $i=0, n$ for $D_{n+1}^{(2)}$, and $i=n$ for
$A_{2n}^{(2)}$. A perfect crystal graph for $D_4^{(3)}$ is constructed as a
by-product.
