You are my senior by five years.
You are five years my senior.
You are older than me by five years.
She is her husband’s junior by two years.
She is two years her husband’s junior.
She is younger than her husband by two years.
至於 “be senior to” 和 “be junior to” 指的是職位的高低或資歷的深淺。例如：
He’s senior to me, though he’s younger. (雖然他比我年輕，但職位卻比我高)