Must vs Ought vs Should

Quando usar cada um em inglês, com significado, registro e exemplos.

Must

Bloco de alta frequência A1

Ought

Formal Top 3000 (comum) B1

Should

Top 1000 (muito comum) A1

Mais formal: Ought

	Must	Ought	Should
Pronúncia	🇬🇧 /["/məst//mʌst/","/ˈmʌsnt/"]/ 🇺🇸 /["/məst//mʌst/","/ˈmʌsnt/"]/	🇬🇧 //ɔːt// 🇺🇸 //ɔt//	🇬🇧 /["/ʃəd//ʃʊd/","/ˈʃʊdnt/"]/ 🇺🇸 /["/ʃəd//ʃʊd/","/ˈʃʊdnt/"]/
Significado	Something that is necessary or very important.	should or must do something	used to tell someone what is the right thing to do
Exemplo	You must finish your homework before playing outside.	You ought to apologize for your mistake.	You should study for the exam to do well.
Registro	Neutro	Formal	Neutro
Quão comum	Bloco de alta frequência	Top 3000 (comum)	Top 1000 (muito comum)
Nível CEFR	A1	B1	A1
Colocações	must see, must do, must have, must remember	ought to know, ought to be, ought to do	should do, should have, should not, should consider, should remember
Antônimos	can, may, might	ought not, should not	must not, shall not
Erros comuns	Using 'must' in situations where 'have to' is more suitable., Confusing 'must' with 'might' or 'may', which imply possibility instead of necessity., Using 'must' with the gerund form instead of the base form of the verb.	Confused with 'should' – they are similar but 'ought' sounds more formal., Using 'ought' without 'to', e.g., 'You ought study.' which is incorrect., Incorrectly using 'ought' in negative forms like 'oughtn't' in some dialects.	'Should' is often confused with 'must,' leading to weaker advice than intended., Forget to follow 'should' with the base form of the verb, e.g., saying 'should goes' instead of 'should go.', Using 'should' for past events instead of 'should have.'
Notas de uso	Use 'must' when giving strong advice or making strong recommendations. Avoid using it in casual conversations where 'should' might be more appropriate.	Use 'ought' in advising or suggesting. It sounds more formal than 'should' and is less common in everyday conversation.	Use 'should' for advice, suggestions, or expectations. It's appropriate in both spoken and written English, but avoid it in very formal contexts where 'ought to' might be preferred.

Perguntas frequentes: Must vs Ought vs Should

Qual é a diferença entre Must, Ought e Should?

Must: Something that is necessary or very important. Ought: should or must do something Should: used to tell someone what is the right thing to do

Qual é mais formal: Must, Ought e Should?

Ought é a mais formal entre elas.

Qual é mais avançada: Must, Ought e Should?

Ought é o nível mais alto, em B1, na escala CEFR.

Must, Ought e Should estão no mesmo nível CEFR?

Must: A1, Ought: B1, Should: A1 na escala CEFR.

Pode mostrar um exemplo de cada?

Must: You must finish your homework before playing outside. Ought: You ought to apologize for your mistake. Should: You should study for the exam to do well.

Posso usar Must, Ought e Should de forma intercambiável?

Nem sempre. Must, Ought e Should são relacionadas e às vezes se sobrepõem, mas diferem em registro, frequência e uso, então trocar uma pela outra pode mudar o sentido ou o tom. Veja as diferenças acima antes de substituir.