senior, junior + to
He is junior to me. 他年纪比我轻。
I am senior to him. 我比他年长。
He's junior to me by two years. = He's two years junior to me.
I am senior to him by two years. = I am two years senior to him.
I am junior to many people in this company.
Many people are senior to me in this company.
In the army, a captain is junior to a major.
In the army, a general is senior to a major.