"You drink milk."
Translation:Você bebe leite.
In portuguese, the singular you is different from the plural you. We've got Você (singular) and Vocês (plural)
And that is not all. The second person in conjugation tables is not "Você". The second person is "Tu". The plural second person is "Vós" The conjugations for the second person are:
Tu bebes (You drink)
Vós bebeis (You drink plural)
But "Você" doesn't follow the standard conjugation It also means "you", but takes conjugation of the third person (Ele, Ela)
Você Bebe = You drink(conjugation = Ele bebe)
Vocês Bebem = You drink plural (conjugation = Eles bebem)
I think it's just because of a matter of consistency. If "the" isn't present in the English sentence, then "o" shouldn't be in the Portuguese sentence either. There are slight differences in meaning between the sentence with "the/o" and the sentence without; if you understand the difference in English, you will understand it as well in Portuguese.
Paulenrique told on another sentence that the rule was something like: no "the" before food, unless the food is definite by something more: example: "bebo o leite de soja" (I drink soja milk), but I'm not sure about this example, if someone could correct if it's wrong, thanks.
I'm not sure about this rule. Your example , "I drink soja milk", is perfectly translatable to "eu bebo leite de soja", without the "o". The "o" is used to say you drink something specific right now, rather than something you drink regularly.
The rule for me is the same as the one in English: if the English sentence has "the", then the Portuguese sentence has "o/a", otherwise it doesn't need it.