For ability:
* Poder: This is the most common and general way to say "can" in Portuguese.
* Example: "Eu posso falar português." (I can speak Portuguese.)
* Saber: This is used for abilities that involve knowledge or skill.
* Example: "Eu sei nadar." (I can swim.)
For permission:
* Poder: This is also used to ask for permission.
* Example: "Posso usar seu telefone?" (Can I use your phone?)
* Permitir: This word means "to allow" and is sometimes used instead of "poder" for permission.
* Example: "Permite que eu use seu telefone?" (Do you allow me to use your phone?)
For possibility:
* Poder: This can also be used for possibilities.
* Example: "Isso pode acontecer." (This could happen.)
The best translation for "can" depends on the specific situation and what you're trying to convey.