首先，以下是各學級的英文:
school = 泛指任何學校
primary school = elementary school = grade school = 小學
junior high school = middle school = 初中/國中
high school = 高中
college = university = 大學
再來，他是大我三屆的學長，可以說:
He's three years my senior in (my) school. (my 可以更確認是同一個學校，但不用也行。)
也可以不提年份，直接說:
He's my senior in (my) school.
以下是另一種說法。我跟他在同一所大學，他是大我一屆的學長:
He is one year ahead of me in college. (常用)
He is one year my senior in college. (常用)
以下有更多例句:
我的大我一年的國中學長正在追我 = A guy who's one year my senior in middle school is pursuing me. = A guy who's one year ahead of me in middle school is pursuing me.
我的大學學長正在追我 = My senior in college is pursuing me.
He is two years ahead of me in school = 他是我學長，大我兩年
He was two years ahead of us = 他比我們大兩屆
另外，We went to the same college. He was a senior. I was a freshman. 就表示他是12年級，我是9九年級。
以下說法表示我們去同一個學校求學過:
We went to the same school.
We were in school together.
順道一提，alumni 是指校友，但你不能說 He's my alumni. 可以說 He's a fellow alumni. 或 He's a fellow alumnus. 詳情請猜考
「校友」的英文怎麼說。
注意，upperclassmen 不指學長或學姊；underclassmen 也不指學弟或學妹。
