YOU SAID:

ooh it mustve been about 7 8 years ago

INTO JAPANESE

ああ、それは約78年前だったに違いない

BACK INTO ENGLISH

Oh, it must have been about 78 years ago

INTO JAPANESE

ああ、それは約78年前だったに違いありません

BACK INTO ENGLISH

Oh, it must have been about 78 years ago