  The cross-sections and analyzing powers for $(p,n)$ reactions on ${}^{3}{\rm
He}$ and ${}^{4}{\rm He}$ have been measured at a bombarding energy of $T_p$ =
346 MeV and reaction angles of $\theta_{\rm lab}$ =
$9.4^{\circ}$--$27^{\circ}$.
  The energy transfer spectra for ${}^{3}{\rm He}(p,n)$ at large $\theta_{\rm
lab}$ ($\ge$ $16^{\circ}$) are dominated by quasielastic contributions, and can
be reasonably reproduced by plane-wave impulse approximation (PWIA)
calculations for quasielastic scattering.
  By contrast, the known $L$ = 1 resonances in ${}^{4}{\rm Li}$ are clearly
observed near the threshold in the ${}^{4}{\rm He}(p,n)$ spectra.
  Because these contributions are remarkable at small angles, the energy
spectra are significantly different from those expected for quasielastic
scattering.
  The data are compared with the PWIA calculations, and it is found that the
quasielastic contributions are dominant at large $\theta_{\rm lab}$ ($\ge$
$22^{\circ}$).
  The nuclear correlation effects on the quasielastic peak for ${}^{4}{\rm
He}(p,n)$ are also discussed.
