Phrase
up on
adjective
熟悉；通晓；了解（最新情况）
knowing the latest information or details about something; up to date on
- 1.
being up to particular standard or level especially in being up to date in knowledge
达到特定标准或水平,尤其是知识更新
达到特定标准或水平,尤其是知识更新；熟悉；精通
In use
She is always up on the latest fashion trends.
Before the exam, I made sure I was up on all the key dates.
Are you up on the new company policy yet?
Learner notes
Grammar Note
通常用于be动词后，表示对某事物熟悉或精通。
Dictionary facts from ECDICT, WIKTIONARY.