What is ‘must’ for?
We use must to talk about things that are very important. It shows a strong obligation or a rule.
- Obligation or Necessity: When something is necessary to do. For example, Students must wear a uniform.
- Strong Advice: When you think something is a very good idea. For example, You must visit the museum; it’s amazing!
🎓 Learn English with the Blended method
Small groups · 24/7 AI Tutor · Cambridge preparation
Plans from ₽39 ₽79 per month
What is 'mustn't' for?
We use mustn't (or must not) to talk about things that are not allowed. It shows a prohibition.
- Prohibition: When something is forbidden or against the rules. For example, You mustn't take photos in the museum.
- Danger: When something is dangerous to do. For example, Children mustn't play with knives.
How do we form sentences with 'must' and 'mustn't'?
Must and mustn't are easy to use! They are modal verbs, so they follow simple rules.
- Always use the base form of the verb: After must or mustn't, the next verb is always in its basic form (e.g., go, eat, study).
- No 'to': We do not use to after must or mustn't.
- No '-s' for 'he/she/it': Must never changes its form, even for he, she, or it.
| Subject | Positive Form | Negative Form |
|---|---|---|
| I / You / We / They | must go | mustn't go |
| He / She / It | must go | mustn't go |
Examples
- I must finish my homework before dinner.
- You must be quiet in the library.
- He must wear a helmet when he rides his bike.
- We mustn't talk during the exam.
- She mustn't forget her passport for the trip.
- They must arrive on time for the meeting.
Practice
💬 Need personalized guidance?
As an Authorized Cambridge Preparation Centre, we can guide you to the right course and certification. Chat with our advisors today.
Chat with an Advisor on WhatsAppCommon mistakes for Spanish speakers
Many Spanish speakers make small mistakes with must and mustn't. Here are the most common ones to avoid:
- Using 'to' after must or mustn't:
- ❌ You must to study.
- ✅ You must study.
- Adding '-s' to must for 'he', 'she', 'it':
- ❌ He musts go.
- ✅ He must go.
Frequently asked questions
What is the main use of 'must'?
Must is for strong rules, obligations, or things that are very important to do. For example, You must listen to your parents.
What is the main use of 'mustn't'?
Mustn't is for things that are not allowed or forbidden. For example, You mustn't run in the corridors.
Can I say 'must not' instead of 'mustn't'?
Yes, must not is the full form, and mustn't is the short, common form. They mean the same thing.
Does 'must' change for 'he/she/it'?
No, must never changes its form. It is always must for all subjects (I, you, he, she, it, we, they).
0 Comments