YOU SAID:

i have not heard that in donkey's years

INTO JAPANESE

私はロバの年に聞いたことがない

BACK INTO ENGLISH

I have never heard of a donkey year

INTO JAPANESE

ロバの年を聞いたことがない

BACK INTO ENGLISH

Never heard of a donkey's year

INTO JAPANESE

ロバの年を聞いたことがない

BACK INTO ENGLISH

Never heard of a donkey's year