MAIS: sense of additon
MAS: sense of opposition
Hello, is very simple my dear....
MAS is equal BUT, we used it when want to say something to continue de explanation, for ex: I'm happy but my legs are pain, in portuguese, Eu estou feliz MAS minhas pernas estão doendo.
MAIS is equal PLUS, we used it when want to compare somethings, for ex: You are more intelligent than me, in portuguese, Você é MAIS inteligente do que eu
Did you understand? Write me and i'll teach you more things about the portuguese language.