Prevent Someone from Doing Something

A Clear Guide to This Essential English Structure

What Does “Prevent Someone from Doing Something” Mean?

The phrase “prevent someone from doing something” means to stop or keep a person from carrying out an action. It’s a common verb pattern in English used to express that an obstacle, rule, person, or situation blocks an activity.

Example: The heavy rain prevented us from going hiking.

Grammar Structure

The correct structure is:

⚠️ Note: You must include “from”. Saying “prevent someone doing something” (without “from”) is common in informal British English but considered incorrect in standard/formal usage—especially in American English and exams like IELTS or TOEFL.

✅ Correct: The fence prevents animals from entering the garden.
❌ Incorrect: The fence prevents animals entering the garden. (Avoid in formal writing)

Common Mistakes

Quick Practice

Which sentence is grammatically correct?

A) The law prevents companies pollute.
B) The law prevents companies from polluting.
C) The law prevents companies to pollute.

More Examples in Context