大一：freshman 英 [ˈfreʃmən] 美 [ˈfrɛʃmən]
大二：sophomore 英 [ˈsɒfəmɔ:(r)] 美 [ˈsɑ:fəmɔ:(r)]
大三：junior 英[ˈdʒu:niə(r)] 美[ˈdʒunjɚ]
大四：senior 英[ˈsi:niə(r)] 美[ˈsinjɚ]
拓展资料：
关于大一、大二、大三、大四的例句：
1.This is my first year of college. I'm a freshman.
这是我进入学院的第一年，我是新生。
2.I was a student. a freshman at college.
我是一个学生，大一新生。
3.Now I have done this in a sophomore seminar, and I did it in a graduate seminar.
我在大二研讨课里这样做了，在研究生研讨课也这样做了。
4.When I was a sophomore, I took part in the secretary department of student union.
我在大二的时候参加了校学生会的秘书部。
5.Her students are usually approached by employers in their junior year because they are trained to do practical work.
她所在学院的学生通常在大三时便已经与用人单位打交道了，因为他们接受训练，做些实践性较强的工作。
6.Exchange programs are mostly available for junior and sophomore students.
交换生课程主要针对大二和大三的学生。
7.I am a senior university student, and this semester I only have one class.
我是一个大四学生，这学期我只有一门课。
8.And he was taking this class second semester of his senior year.
他是在他大四的第二个学期，上的这门课。