Understanding Must and Must Not in English
This page provides a detailed explanation of how to use "must" and "must not" (mustn't) in English, with a focus on school-related examples and rules.
Definition: "Must" expresses obligation or necessity - things that one has to do, while "must not" (mustn't) expresses prohibition - things that are not allowed.
Example: "I must do my homework" demonstrates positive obligation, while "I must not sleep in class" shows prohibition.
Vocabulary:
- Must = avoir l'obligation de
- Must not/Mustn't = ne pas avoir le droit de
- Homework = devoir
- Corridors = couloirs
Highlight: The exercise section includes five practical examples of classroom rules where students need to determine whether "must" or "must not" should be used:
- Behavior regarding chewing gum in class
- Rules about running in corridors
- Attitude towards teachers
- Proper disposal of papers
- Rules about writing on tables
Quote: "I must do my homework" - This key example demonstrates the basic structure for expressing obligation in English.


