i don't know whether it will rain or not .but if it __.i shall stay at homewilldiddoesshall

i don't know whether it will rain or not .but if it __.i shall stay at homewilldiddoesshall
i don't know whether it will rain or not .but if it __.i shall stay at home
will
did
does
shall

i don't know whether it will rain or not .but if it __.i shall stay at homewilldiddoesshall
does

does

does

does
因为后面I跟了个shall，带有将来的意思
这里是时间状语从句

does
此句为if引导的条件壮语从句，所以主句用一般将来时，那么从句就用一般现在时，所以用does

will.