upon

The preposition 'upon' indicates position on or above a surface, immediate temporal succession ('immediately after'), basis or foundation for action, formal or literary emphasis, dependence or reliance, and occurrence or discovery in formal contexts.

• 🇨🇳介词 upon 表示在……之上或表面接触，也可表示紧接着发生（一……就），以及依据、凭借或依赖某事物，常用于正式或文学语境。

1. Position on or above a surface B1 formal

   Indicates physical location on top of or in contact with the upper surface of an object, often with formal or literary tone

   • The book lay upon the table
   • She placed the crown upon his head
   • The castle stands upon a hill

   🇨🇳在……上，在……上面

2. Immediate temporal succession B2 formal

   Indicates that an action occurs immediately after or at the moment of another event

   • Upon arriving, she called home
   • Upon hearing the news, he resigned
   • The decision was made upon reflection

   🇨🇳一……就……；立即

3. Basis, foundation, or ground for action B2 formal legal

   Indicates the reason, evidence, or authority on which an action, decision, or belief is based

   • The verdict was based upon the evidence
   • She acted upon good advice
   • The theory rests upon several assumptions

   🇨🇳依据，根据

4. Dependence or reliance B2 formal business

   Expresses that something depends on, relies on, or is contingent upon a particular condition or factor

   • Success depends upon hard work
   • The project hinges upon funding
   • His decision rests upon your approval

   🇨🇳取决于，依赖于

5. Formal/literary emphasis or occurrence C1 formal art

   Used in formal or literary contexts to add emphasis, dignity, or stylistic weight to a statement, often indicating sudden occurrence or discovery

   • Once upon a time, there lived a king
   • Upon further investigation, the truth emerged
   • He stumbled upon a rare manuscript

   🇨🇳一旦，在……之际，突然

6. Attack, assault, or sudden action B2 formal art

   Indicates a sudden or forceful action directed at someone or something, often in military, literary, or dramatic contexts

   • The army fell upon the enemy
   • Doubts began to creep upon him
   • Silence fell upon the crowd

   🇨🇳向…袭击，扑向