Must/have to (Modals)

Intermediate (B1)en
Must/have to

Modals of Obligation — Must and Have to 


In this lesson, you will learn how to talk about obligation — things that are necessary or required. 

1. What Obligation Means
Obligation is about things that are necessary, required, or expected. 

Examples: 
  • “You must wear a seatbelt.”
  • “I have to wake up early tomorrow.”


2. Using Must
We use must when the obligation comes from the speaker or from a strong personal feeling.
 
Examples:
  • “I must finish this report today.”
  • “You must try this cake.”


3. Using Have to
We use have to when the obligation comes from rules, laws, or external situations.
 
Examples:
  • “I have to wear a uniform at work.”
  • “We have to show our passports at the airport.”

Note: The past form of “have to” is had to for obligations in the past. 


4. Must vs Have to — Meaning Difference
Compare how the source of obligation changes the meaning.
 
Examples:
  • “I must study tonight.”
     → Personal decision.
  • “I have to study tonight.”
    → The situation requires it.


5. Negative Forms (Important Difference)
The negative forms have very different meanings.
 
Examples:
  • “You mustn’t park here.”
     → It is not allowed.
  • “You don’t have to come tomorrow.”
    → It is not necessary.


6. Key Takeaway
  • Must shows strong, personal obligation.
  • Have to shows external obligation.
  • Mustn’t means prohibition.
  • Don’t have to means no obligation.

Practice Exercises

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Must/have to

B1
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Related Vocabulary

Expand your vocabulary with words related to this grammar topic

Must/have to

B1

Modals (Must/Have to)

2 words
must

verb

B1

Used to express necessity or obligation.

You must finish your homework before going out.

have to

Created: January 3, 2026