"We go bowling on Friday." means that you are going bowling on Friday. It is possible that this is your regular bowling day, but I would certainly not know that from this statement. "We go bowling on Fridays." leaves no room for doubt. Yes, if you previously told me that you are in a league that meets weekly, then I would know; but the singular Friday by itself does not mean a weekly event. You could say "every Friday" or "Fridays" to mean a weekly event or you could use the singular with the adverb "always" indicating that the verb is repeated every Friday or with the adverb "usually" which indicates repetition of almost every Friday.
@everybody - re: this question and answer could really use some up votes.
Hola duo amigos. Cantabrian rises an important point with his translations. Allintolearning points out that Cantabrain's translations don't convey the meaning of the root sentence.
My feeling is that because Cantabrain's translations are wrong, his comment was initially voted down the list.
However, Allintolearning's great explanation is being dragged down the list too. This is unfortunate because he's dead on the money.
At this point, voting both comments up the list would facilitate more users seeing this very important point about the function of the singular definite article (el) in relation to a singular event which occurs one particular time (on Saturday ) as opposed to the plural definite article (los) and a series of regularly occurring (on Saturdays) habitual events.
It seems counter intuitive to vote up a mistaken idea. But the response that it elicited is too good to let sink.
except that cantabrian is right. allintolearning is ignoring the verb tense -- simple present tense can be used for habitual/repeated action, so as lonzcat noted you have to look at the context, not just whether the day has an -s on it. (this is for english; if i knew spanish well enough to have an opinion on this, i wouldn't be here.)
Who would say "On saturdays we eat flesh?" The better question is when is carne meat and when is carne Beef? I answered We eat beef on Saturdays and was marked wrong because it wanted "meat" instead. What the heck kind of meat are we talking about here? It's not pollo o pescado...
Because carne is not an abstract noun, and you are not talking about some specific meat.