  While EMC-SMC-E142 data sheds new light on the behavior of polarized parton
distributions at small and intermediate $x$, it may be also interesting to
study valence quark polarizations at large $x$, where spectator quark counting
rules and Carlitz-Kaur type models predict different behavior for down quark
polarizations. The article examines the possibility of testing the ratio
$\Delta d_V(x)/d_V(x)$ at $x\to 1$ in the inclusive production of
$W^{-}$-bosons.
