Someone had started eating in a sukkah (and made a "leishev") then after some time it started to rain. They moved into their house and waited then for the rain to stop. When the rain stopped they ...
If I recall correctly the reason we eat a Seuda on Hoshanah Rabah is it is the last day we have a Chiuv to eat in the Succah. Suppose it is raining and you can not eat in the Succah do you still have ...