must, have to and should: rules, obligations and advice
Say what's necessary, what's not allowed, what isn't necessary, and give advice
What you'll be able to do
Explain rules at work, school or in a building, say what you need to do, and give friendly advice.
The meanings
| Form | Meaning | Example |
|---|---|---|
| must / have to | it's necessary | You must wear a helmet. I have to work on Saturday. |
| mustn't | it's not allowed | You mustn't smoke here. |
| don't have to | it isn't necessary (you can if you want) | You don't have to come; it's optional. |
| should / shouldn't | advice: it's a good idea / a bad idea | You should see a doctor. |
- You must show your passport at the gate.a rule
- I have to finish this report today.an obligation
- You mustn't park here.not allowed
- You don't have to bring anything.not necessary
- You should try the soup.advice
mustn't and don't have to are very different: You mustn't tell her (it's a secret) vs You don't have to tell her (you can, but it isn't necessary).
Past
Must has no past form for obligation: use had to. I had to wait for an hour.
Common mistakes
You must to go.No to after must: You must go.She have to work.→ She has to work.I musted leave early.→ I had to leave early.You mustn't pay; it's free.If it's free, payment isn't necessary: You don't have to pay.
Practice
- Entry is free, so you _____ pay.Options: don't have to · mustn't · should
Show the answer
don't have to — Not necessary: don't have to.
- You _____ use your phone during the exam. It's against the rules.Options: mustn't · don't have to · should
Show the answer
mustn't — Not allowed: mustn't.
- You look tired. You _____ go to bed earlier.Options: should · mustn't · don't have to
Show the answer
should — Friendly advice: should.
- She _____ wear a uniform at work.Options: has to · have to · must to
Show the answer
has to — She takes has to; no to after must.
- Yesterday I _____ (have to) wait an hour for the bus.
Show the answer
had to — The past of must / have to is had to.
In the app, this lesson is taught one idea at a time with the examples read aloud, then practised with questions you answer by choosing or typing. It comes back for review on later days, until you can use it without help.
More on this topic: English modal verbs: must, have to, should and more