  For any subcritical index of regularity $s>3/2$, we prove the almost global
well posedness for the 2-dimensional semilinear wave equation with the cubic
nonlinearity in the derivatives, when the initial data are small in the Sobolev
space $H^s\times H^{s-1}$ with certain angular regularity. The main new
ingredient in the proof is an endpoint version of the generalized Strichartz
estimates in the space $L^2_t L_{|x|}^\infty L^2_\theta ([0,T]\times \R^2)$. In
the last section, we also consider the general semilinear wave equations with
the spatial dimension $n\ge 2$ and the order of nonlinearity $p\ge 3$.
