[bmo]

I am confused. Which are correct?

1. I was a teacher for 18 years before coming to the U.S.
2. I was a teacher for 18 years before coming to the U.S. in 1980.
3. I was a teacher for 18 years before I came to the U.S.
4. I had been a teacher for 18 years before I came to the U.S.

Thanks.

BMO