If you try to translate portuguese to english you may not get there.
Could is a past tense of Can and We use Could to say that something is possible in the future, but it's not a hundred %. I mean, you MIGHT lose your driving license or not.
Btw: Follows the modal verbs sorted by relevance (Strongest Possibility)
Must > Shall > Will > Can > May > Should > Could > Would > Might
I had never learned this before I came to England.