junior是大三学生，senior是大四学生。另，freshman是大一，sophomore是大二。
例句
She\'s his junior by four years.
她比他小四岁。
Junior nurses usually work alongside more senior nurses.
初级护士通常和较高级的护士一起工作。
He was the senior serving naval officer.
他曾是高级现役海军军官。
Senior defence officials held private talks.
高级防务官员举行了秘密会谈。
