I put "The cat takes your milk" and got it wrong. From reading everyones comments, i understand that 'toma' here would usually refer to drinking. So what if the cat JUST took the milk (eg dragged a milk carton away)? Also, I put 'your' for Seu, others put 'his'. Would teu only mean 'your' and seu could be either depending on context?
For the meaning of tomar = we can't really know for sure. My first thought reading the sentence was that the cat was drinking its milk. But tomar as in take away is, technically, correct, although it's quite rare to hear it used like that nowadays.
As for the seu = it refers to você, but ALSO to ele/ela (because você uses all the same forms as the third person singular).
In conversation, it's much more common to use dele/dela for ele/ela, to avoid confusion - but seu is still officially used for ele/ela, as well as você C:
Oh, teu refers to tu - so using it causes no confusing whatsoever, but it's not so common as the tu form is used only in a few places!