YOU SAID:

I used to eat frogs but

INTO JAPANESE

カエルを食べていましたが、

BACK INTO ENGLISH

I used to eat frogs

INTO JAPANESE

カエルを食べていました

BACK INTO ENGLISH

was eating a frog

INTO JAPANESE

カエルを食べていた

BACK INTO ENGLISH

ate a frog

INTO JAPANESE

カエルを食べた

BACK INTO ENGLISH

ate a frog