Qual é a diferença entre since e as e because ?Podes indicar apenas respostas exemplo.

This is a difficult question. They're not used completely interchangeably but I reckon you can take any sentence with either as or since and substitute because and it will still make sense (at least for the uses of as and since as conjugations), though perhaps it will sound slightly unusual in some cases. I would say that since is normally used for quite clear implications. So I could say "The correct direction must be left or right and since it's not left it must be right." However I wouldn't normally say "We're going left since I want to go left." It think it would sound more natural to use because here. I failed to think of better examples as I'm not very good at thinking of them (as is the best choice here and I'm not entirely sure why!)