upon用英语单词怎么说

Upon是一个介词，意思是“在…之上”，“在…之后”。在英文中，它通常用于表示时间关系，表示某一件事情在另一件事情之后发生。例如：

Upon my arrival at the airport, I reapzed that I had left my passport at home.

我到达机场后才发现我把护照留在家里了。

Upon receiving the news, he became very upset.

他一听到这个消息就很激动。

Upon further investigation, it was revealed that the witness had ped.

经过进一步调查，发现该证人撒了谎。