  We consider a one-dimensional lattice model with the nearest-neighbor
interaction $V_1$ and the next-nearest neighbor interaction $V_2$ with filling
factor 1/2 at zero temperature. The particles are assumed to be spinless
fermions or hard-core bosons. Using very simple assumptions we are able to
predict the basic structure of the insulator-metal phase diagram for this
model. Computations of the flux sensitivity support the main features of the
proposed diagram and show that the system maintains metallic properties at
arbitrarily large values of $V_1$ and $V_2$ along the line $V_1-2V_2=\gamma J$,
where $J$ is the hopping amplitude, and $\gamma\approx1.2$. We think that close
to this line the system is a ``weak'' metal in a sense that the flux
sensitivity decreases with the size of the system not exponentially but as
$1/L^\alpha$ with $\alpha>1$.
