prevent 通常会接所有格形容词 + 动名词或接受词 + from + 动名词。当主词没有必要列出时，prevent 可以直接接动名词，也可以接名词。
举例
- You can't prevent my leaving.
- You can't prevent me from leaving.
- I want to prevent his getting sick.
- I want to prevent him from getting sick.
- This campaign is designed to prevent drowning.
- Preventing stealing is our main goal this year.
- We are working to prevent forest fires.
- This vaccine will prevent malaria.