This website might be useful: http://context.reverso.net/translation/portuguese-english
They offer the words in context, as used in Portuguese, although the English translations are sometimes questionable. It seems like 'às tardes' translates as 'in the afternoons' - plural, non-specific and frequently repeated. But 'as tardes' (no accent over a) can mean 'afternoon(s)' or 'evening(s)', with variable frequency/specificity.
The accent mark also indicates, otherwise it would be "as" without the absent mark if just referring to a definite article. We see this in other situations where you do an action to something with "a" as the definite article. Instead of saying VERB a a OBJECT, the two "a" 's are combined and the accent mark shows up (hopefully that was a clear explanation).
Thank you for clarifying. But they don't say that in the translation they give you. Are we supposed to know this already? :/
...with the word á y a the one with the accent means to and the one without means the.
I do not think this is the case in Portuguese (maybe in Spanish which also uses "y" for the word, and rather than the accentless "e" in Portuguese). The preposition (to) and the article (the) are spelled the same, "a" with no accent when separate, but when they contract they get the grave accent (to the left, rather than the more common acute accent) to show the double "a" has been joined together.
Supposedly there is no difference in pronunciation in Brazil (nor with há) but there is in Portugal (same with há). Would be great if some natives from Portugal would add to Forvo so we can all hear.
It's not spelled the same in fact. It's a bit difficult to explain the difference but it's kinda like "that" and "than" (you don't spell the "a" the same way).
"à" it's kinda like if you were screaming xD (AAAHHHHHH)
"a" its spelled like in "than"
You can ear it right on Google's translator