grammar - what is the past tense of お腹が空いた?

if お腹が空いた means "I'm hungry",

then what would be the past tense of お腹が空いた since (i think) it's already in the past tense?

Answer

The past tense would be:

お腹がすいていた

This would be along the lines of "my stomach was in the state of being empty" or simply "I was hungry."

Additionally, the "た” in お腹がすいた is not showing "past tense" but is actually showing the completion of an action. In this case, the stomach has emptied.

食べた後で部屋を掃除します。This is the "た” which shows completion of an action.

昨日ケーキを５個食べた！ This is the past tense version of "た".

I believe this た is called 完了形 in grammar terms.