I can say what I have to do and what I know how to do: “Tenho de arrumar a casa”, “Sei nadar”, “Não sei onde é a estação”.
I have to and I know how
I have to and I know how
To say what you have to do and what you know how to do, you need three forms.
“ter de” + infinitive — “have to, must”: “Tenho de esperar em casa”. You know the forms of “ter”, and the “de” never disappears. People also say “ter que” — it isn't a mistake when others say it, but we write “ter de”.
“dever” + infinitive — “should, must”, for advice and rules: devo, deves, deve, devemos, devem.
“saber”: sei, sabes, sabe, sabemos, sabem. With an infinitive it means “know how to”: “Sei cantar”. With a fact it means “know”: “Não sei”, “Sabes onde é a garagem?”
English “can” covers two Portuguese verbs: “Sei cantar” — I can sing, I've learned how; “Posso cantar” — I'm allowed to, I have the chance. The table is next to this text.
Common mistakes:
• NOT “Tenho arrumar o quarto” — the “de” never disappears: “Tenho de arrumar o quarto.”
• NOT “Sei a cantar” — no preposition after “saber”: “Sei cantar.”
• NOT “Eu deve sair” — the person form: “Eu devo sair.”
I have to, I should, I know how
All three take an infinitive after them; ter keeps its de.
| Form | Meaning | Example |
|---|---|---|
| ter de + infinitive | have to, must | Tenho de esperar |
| dever + infinitive | should, must | Deves chegar cedo |
| saber + infinitive | know how to | Sei nadar |
| saber + a fact | to know | Não sei onde é |
English “can”: two Portuguese verbs
Portuguese keeps ability and possibility apart.
| Form | What it means | Example |
|---|---|---|
| sei + infinitive | I know how to, I've learned how | Sei cantar |
| posso + infinitive | I'm allowed to, I have the chance to | Posso cantar aqui |
Lesson notes
I have to and I know how
To say what you have to do and what you know how to do, you need three forms.
“ter de” + infinitive — “have to, must”: “Tenho de esperar em casa”. You know the forms of “ter”, and the “de” never disappears. People also say “ter que” — it isn't a mistake when others say it, but we write “ter de”.
“dever” + infinitive — “should, must”, for advice and rules: devo, deves, deve, devemos, devem.
“saber”: sei, sabes, sabe, sabemos, sabem. With an infinitive it means “know how to”: “Sei cantar”. With a fact it means “know”: “Não sei”, “Sabes onde é a garagem?”
English “can” covers two Portuguese verbs: “Sei cantar” — I can sing, I've learned how; “Posso cantar” — I'm allowed to, I have the chance. The table is next to this text.
Common mistakes:
• NOT “Tenho arrumar o quarto” — the “de” never disappears: “Tenho de arrumar o quarto.”
• NOT “Sei a cantar” — no preposition after “saber”: “Sei cantar.”
• NOT “Eu deve sair” — the person form: “Eu devo sair.”