  Without assuming any solar models and neutrino flavor conversions, $^8$B
neutrinos seen by the Kamiokande experiment should contribute 2.6$\pm 0.45$ SNU
to the chlorine experiment. When this rate is compared with the total event
rate of 2.3$\pm 0.2$ SNU observed by the Homestake experiment which should
inlude a 0.2 SNU contribution from uncertainty-free pep neutrinos, there may
still be a possible evidence that $^7$Be neutrinos are more severely suppressed
than the $^8$B neutrinos with respect to the predictions of standard solar
models, which cannot be explained by any known astrophysics solution. Given a
Kamiokande event rate of larger than 36$\%$ (2$\sigma$) of the prediciton of
Bahcall and Pinsonneault's standard solar model, variations of standard solar
models yield minimal rates of 3.6 SNU for the Homestake experiment and 114 SNU
for GALLEX and SAGE. Therefore, variations of standard solar models as
solutions to the solar neutrino problem are so far inconsistent with the
Homestake experiment and only marginally allowed by the gallium experiments. If
the gallium experiments confirm a flux significantly below 114 SNU, it would
imply unconventional physics.
