B2 · Intermediário superior Capítulo 18

Regras, Permissões e Escolhas: Dominando os Verbos Modais

4 Regras totais
20 exemplos
1 min
Regras neste capítulo Prática rápida

Chapter in 30 Seconds

Master the nuances of modal verbs to express rules, requirements, and permissions with total confidence.

  • Distinguish between internal and external obligations.
  • Navigate the subtle differences between prohibition and absence of necessity.
  • Express formal and informal permissions using standard and alternative phrases.
Command the rules of English with precision.

O que você vai aprender

Pronto para elevar seu inglês ao próximo nível? No nível B2, a diferença entre soar como um iniciante e um falante fluente está nos detalhes — e nada é mais detalhado do que o uso dos verbos modais. Neste capítulo, você vai dominar a arte de expressar obrigações, permissões e necessidades com a precisão de um nativo. Vamos mergulhar nas sutilezas de 'must' e 'have to' para que você saiba exatamente quando falar de uma regra oficial ou de um sentimento pessoal. Você aprenderá a diferença crucial entre 'mustn't' (proibido!) e 'don't have to' (totalmente opcional!), evitando gafes em situações sociais ou no escritório. Também vamos explorar o passado, comparando o que você não precisava fazer ('didn't need to') com o que você fez sem necessidade ('needn't have'). Imagine-se explicando as regras de um projeto para sua equipe ou entendendo o que é esperado de você em um intercâmbio com estruturas como 'be supposed to'. Ao final deste capítulo, você será capaz de navegar por regulamentos complexos e dar permissões de forma educada e clara. Vamos transformar a gramática em segurança para você se comunicar com autoridade e naturalidade em qualquer lugar do mundo!

Learning Objectives

By the end of this chapter, you will be able to:

  1. 1
    By the end you will be able to: Differentiate between internal and external obligation using must and have to.
  2. 2
    By the end you will be able to: Distinguish between prohibition and lack of necessity in professional contexts.

Dicas e truques (4)

💡

The 'Must' Trap

Avoid using 'must' in questions. It sounds like you are demanding an answer. Use 'Do I have to' instead.
frontend.learn_grammar.from_rule: Obligation and Necessity: Must, Have To, Need To
💡

Context is King

Always ask yourself: Is this a rule or a choice?
frontend.learn_grammar.from_rule: Prohibition vs. No Necessity: Mustn't vs. Don't Have To
💡

Use 'May' for respect

When in doubt in a professional setting, use 'may'.
frontend.learn_grammar.from_rule: Permission: Can, May, Be Allowed To, Be Supposed To
💡

The 'Needn't Have' Trap

Always use 'needn't have' for past mistakes. It shows you know the action was completed.
frontend.learn_grammar.from_rule: Needn't, Don't Need To, Didn't Need To, Needn't Have: No Obligation

Vocabulário-chave (5)

Mandatory Required by rule or law Optional Not required Forbidden Not allowed Authority Power to enforce rules Discretion Freedom to decide

Real-World Preview

briefcase

Office Protocol

Review Summary

  • Must/Have to + base verb
  • Mustn't + base verb
  • Be allowed to/May
  • Needn't/Don't need to

Erros comuns

Must is not used in the negative for obligation; use 'don't have to' instead.

Wrong: I don't must go.
Correto: I don't have to go.

Mustn't means it is forbidden, not that it is optional.

Wrong: You mustn't pay if you don't want to.
Correto: You don't have to pay if you don't want to.

Modals do not take the third-person 's' and are followed by the bare infinitive.

Wrong: He musts to work.
Correto: He must work.

Next Steps

You have done an amazing job today! Keep practicing these nuances, and you will sound increasingly natural.

Listen to a news report and note the modal verbs used to describe laws.

Continue to: Get: Different Meanings and Uses

Prática rápida (10)

Choose the best fit.

___ I ask a question?

✓ Correct! ✗ Not quite. Correct answer: May
May is polite.

frontend.learn_grammar.from_rule: Permission: Can, May, Be Allowed To, Be Supposed To

Fill in the blank.

I ___ to be at the meeting at 9.

✓ Correct! ✗ Not quite. Correct answer: am supposed
Supposed to means expected.

frontend.learn_grammar.from_rule: Permission: Can, May, Be Allowed To, Be Supposed To

Fill in the blank with mustn't or don't have to.

You ___ smoke in the hospital.

✓ Correct! ✗ Not quite. Correct answer: mustn't
It is a rule.

frontend.learn_grammar.from_rule: Prohibition vs. No Necessity: Mustn't vs. Don't Have To

Choose the correct modal.

Employees ___ use the emergency exit unless there is a fire.

✓ Correct! ✗ Not quite. Correct answer: mustn't
It is a safety rule.

frontend.learn_grammar.from_rule: Prohibition vs. No Necessity: Mustn't vs. Don't Have To

Fill in the blank with the correct form.

You ___ wear a seatbelt by law.

✓ Correct! ✗ Not quite. Correct answer: have to
It is an external rule.

frontend.learn_grammar.from_rule: Obligation and Necessity: Must, Have To, Need To

Find the error.

Find and fix the mistake:

You mustn't go if you are tired.

✓ Correct! ✗ Not quite. Correct answer: mustn't
Should be 'don't have to'.

frontend.learn_grammar.from_rule: Prohibition vs. No Necessity: Mustn't vs. Don't Have To

Fix the error.

Find and fix the mistake:

I can to go.

✓ Correct! ✗ Not quite. Correct answer: I can go
No 'to' after 'can'.

frontend.learn_grammar.from_rule: Permission: Can, May, Be Allowed To, Be Supposed To

Choose the correct modal.

You ___ pay for the entry; it's free.

✓ Correct! ✗ Not quite. Correct answer: don't have to
It is not necessary.

frontend.learn_grammar.from_rule: Prohibition vs. No Necessity: Mustn't vs. Don't Have To

Fix the error.

Find and fix the mistake:

You don't must smoke here.

✓ Correct! ✗ Not quite. Correct answer: You mustn't smoke here.
Prohibition requires mustn't.

frontend.learn_grammar.from_rule: Obligation and Necessity: Must, Have To, Need To

Fill in the blank.

You ___ finish the work today; tomorrow is fine.

✓ Correct! ✗ Not quite. Correct answer: don't have to
It is optional.

frontend.learn_grammar.from_rule: Prohibition vs. No Necessity: Mustn't vs. Don't Have To

Score: /10

Perguntas comuns (6)

No, 'must' has no past form. Use 'had to' instead.
Yes, it is often used in formal writing or by authority figures.
No, 'mustn't' is not used in questions. Use 'do I have to' instead.
Yes, it is often used in official rules and signs.
It's better to use 'may' or 'could'. 'Can' might sound too casual.
Modals like 'can' are followed by the base verb without 'to'.
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