Practise this grammar point with a scored quiz, sentence exercises and writing tasks—all with explanations or review guidance.
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A modal is normally followed by the base form: should ask, might arrive, must leave. Must not means prohibited; do not have to means not necessary.
| Use | Example | Why it works |
|---|---|---|
| Advice | You should save your draft. | This recommends an action. |
| Prohibition | You must not share the password. | This says the action is forbidden. |
| No obligation | You do not have to print the notes. | Printing is optional, not forbidden. |
Check: She must to leave
Use: She must leave
Core modals such as must and should take the base verb without to.
Read the example and explain the choice before answering. After the exercise, write a new sentence using the same pattern. Revisit any answer you could not explain, even if you guessed correctly.
4 sets · 40 exercises · about 50–70 minutes with writing and review.
10 scored questions, 20 sentence exercises and 10 writing challenges. Time depends on your pace. Start with the quiz or choose the practice you need.
Your scored quiz and self-reviewed exercises are tracked separately on this device.
Questions 1–5 build confidence; 6–10 check transfer and detail. Use Practice for feedback after each answer, or Test yourself to check at the end.
10 questions · 10 XP per correct answer · explanations included
do not have to. Do not have to removes obligation. Must not would prohibit attendance.
must not. Must not expresses prohibition.
should. Should gives advice and takes the base form.
might. Might expresses a possibility, not certainty.
can. Can expresses permission here.
must not. Must not expresses prohibition; do not have to means there is no obligation.
do not have to. Do not have to means coming is not required, not that it is forbidden.
might. Might expresses uncertainty. Must and has to express stronger necessity or deduction.
should. Should gives advice about what to do now.
could. Could expresses general ability in the past.
Complete the missing words, then compare the expected form. More than one natural answer may be possible; use the cue and explanation.
must not
You must not enter; this area is prohibited. (prohibition)
Use a base verb after a modal. Distinguish ability, advice, possibility, obligation and prohibition from context.
do not have to
You do not have to bring food; lunch is provided. (no obligation)
Use a base verb after a modal. Distinguish ability, advice, possibility, obligation and prohibition from context.
could
I could ride a bike when I was seven. (past general ability)
Use a base verb after a modal. Distinguish ability, advice, possibility, obligation and prohibition from context.
should
You should back up your work regularly. (advice)
Use a base verb after a modal. Distinguish ability, advice, possibility, obligation and prohibition from context.
might
She might be at home; I’m not sure. (possibility)
Use a base verb after a modal. Distinguish ability, advice, possibility, obligation and prohibition from context.
May
May I ask a question? (formal permission)
Use a base verb after a modal. Distinguish ability, advice, possibility, obligation and prohibition from context.
must
We must wear helmets; it is a strict rule. (obligation)
Use a base verb after a modal. Distinguish ability, advice, possibility, obligation and prohibition from context.
can
He can speak three languages. (present ability)
Use a base verb after a modal. Distinguish ability, advice, possibility, obligation and prohibition from context.
cannot
That cannot be our bus; it has the wrong number. (negative deduction)
Use a base verb after a modal. Distinguish ability, advice, possibility, obligation and prohibition from context.
should not
You should not spend all night revising. (advice against)
Use a base verb after a modal. Distinguish ability, advice, possibility, obligation and prohibition from context.
Complete the missing words, then compare the expected form. More than one natural answer may be possible; use the cue and explanation.
might not
They might not come if the weather is bad. (uncertain negative)
Use a base verb after a modal. Distinguish ability, advice, possibility, obligation and prohibition from context.
could not
I could not swim at the age of four. (past inability)
Use a base verb after a modal. Distinguish ability, advice, possibility, obligation and prohibition from context.
must
You must be tired after that long journey. (strong deduction)
Use a base verb after a modal. Distinguish ability, advice, possibility, obligation and prohibition from context.
may
We may need another chair; attendance is uncertain. (possibility)
Use a base verb after a modal. Distinguish ability, advice, possibility, obligation and prohibition from context.
Could
Could you help me carry this box? (polite request)
Use a base verb after a modal. Distinguish ability, advice, possibility, obligation and prohibition from context.
can
She can join us now that her work is finished. (available opportunity)
Use a base verb after a modal. Distinguish ability, advice, possibility, obligation and prohibition from context.
must not
Visitors must not feed the animals. (prohibition)
Use a base verb after a modal. Distinguish ability, advice, possibility, obligation and prohibition from context.
do not have to
You do not have to stay until the end; leaving early is allowed. (no obligation)
Use a base verb after a modal. Distinguish ability, advice, possibility, obligation and prohibition from context.
should
He should ask for clarification if he is unsure. (advice)
Use a base verb after a modal. Distinguish ability, advice, possibility, obligation and prohibition from context.
cannot
I cannot open this jar; the lid is too tight. (inability)
Use a base verb after a modal. Distinguish ability, advice, possibility, obligation and prohibition from context.
Write an original answer for each task. Review the guidance to check your work. These are self-review tasks, not automatic grammar grading.
Your wording can vary.
Use must not plus a base verb.
Check both the form and the meaning. If you are unsure, compare the lesson explanation before marking this exercise reviewed.
Your wording can vary.
Use do not have to, which does not mean forbidden.
Check both the form and the meaning. If you are unsure, compare the lesson explanation before marking this exercise reviewed.
Your wording can vary.
Use should plus a base verb.
Check both the form and the meaning. If you are unsure, compare the lesson explanation before marking this exercise reviewed.
Your wording can vary.
Use could for past general ability.
Check both the form and the meaning. If you are unsure, compare the lesson explanation before marking this exercise reviewed.
Your wording can vary.
Could you plus base verb makes a polite request.
Check both the form and the meaning. If you are unsure, compare the lesson explanation before marking this exercise reviewed.
Your wording can vary.
Use may or might, without presenting it as certain.
Check both the form and the meaning. If you are unsure, compare the lesson explanation before marking this exercise reviewed.
Your wording can vary.
Use must for the deduction and explain the evidence.
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Your wording can vary.
Use cannot for a negative deduction.
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Your wording can vary.
The first prohibits; the second removes obligation.
Check both the form and the meaning. If you are unsure, compare the lesson explanation before marking this exercise reviewed.
Your wording can vary.
A modal takes the bare infinitive: should study.
Check both the form and the meaning. If you are unsure, compare the lesson explanation before marking this exercise reviewed.
Print this lesson’s original questions with a separate answer key. Use the worksheet for another round without looking at the explanations.
Try these two tasks before opening the answers. They practise explanation and writing; they do not change your quiz score.
Repair the meaning: Attendance is optional, so you must not come.
Attendance is optional, so you do not have to come. Must not would forbid attendance.
Write one rule that forbids something and one that makes something optional.
You must not photograph the exhibits. You do not have to leave your bag at reception. The first prohibits; the second allows a choice.
Other wording may be correct. Compare the meaning and verb pattern, not just the words.
Connect a condition to its possible or imagined result.
Extra practice: Must, mustn’t, have to and don’t have to exercises →
Must and have to can both express obligation. Mustn’t means an action is forbidden. Don’t have to means an action is not necessary: you may still choose to do it. Context matters; must and have to are not always interchangeable, but a strict internal-versus-external rule is too simple.
| Pattern | Example | Meaning |
|---|---|---|
| must / have to | You must show your ticket. / You have to show your ticket. | Both can express a requirement in this situation. |
| mustn’t | You mustn’t touch this wire. | Touching it is forbidden; this is not permission to choose. |
| don’t have to | You don’t have to print the ticket. | Printing is optional, not forbidden. |
| past obligation | Yesterday we had to leave early. | Use had to for this past obligation. |
Choose your answer before opening the explanation. These extra self-checks do not change your quiz score.
Mustn’t: the rule prohibits it.
Don’t have to: typing is optional, but allowed.
Have to: it is a requirement. Must would also express obligation here.
Choose the time you have. These are suggested study plans, not timers.
Answer the ten-question quiz. Read the explanation for each mistake before trying again.
Take the scored quiz →30 MINComplete the warm-up, then sets 2 and 3. Compare your answers and correct the patterns you missed.
Open sentence practice →60 MINWork through all four sets. Spend the final part writing, comparing and improving your own sentences.
Explore all four sets →Open the question that matches where you got stuck.
No. Must not prohibits an action: “You must not enter.” Do not have to removes an obligation: “You do not have to attend” means attendance is optional. Confusing them can reverse the message.
After core modals such as can, should and must, use the base verb: “She can swim”, not “can swims” or “can to swim.” Expressions such as have to have a different structure.
A fresh set of 10 questions with explanations. Continue when you are ready.
Next challenge: Conditionals: real & imagined situations →