Translation:Tonight we will drink less beer.
Same. This night. Clearly, the Duolingo folks have never heard the classic Billy Joel song: This night is mine It's only you and I Tomorrow is a long time away This night can last forever
I left out the word 'nós' and the sentence wasn't accepted.
"Esta noite vamos beber menos cerveja."
Is this grammatically correct or should I use 'nós'?
The system accepts omitting nós here.... It's grammatically correct :)
The sentence you posted here is just perfect.
The sentence may be perfect but it's probably not such a good translation. The lack of "nós" means it could be interpreted as the imperative "Tonight let's drink less beer" which is not really the same as the intended meaning of "Tonight we'll drink less beer".
But somehow I can't see an imperative there. It's just not natural.
That too is interesting. From a purely technical point of view "vamos" is both indicative and imperative. Does imperative "vamos" need to be in the right position as in "Vamos tomar um cafezinho!"?
Perhaps "Vamos beber menos cerveja esta noite" doesn't sound like a command whereas "Vamos beber mais cerveja esta noite!" does. :-)
All your examples can be imperative.
But adding "esta noite" before vamos weakens that meaning so much that I'm having a hard time to see the imperative in that case.
For other persons, it would be necessary to add a comma:
- Esta noite, vá ao baile e só volte de manhã = Tonight, go to the ball and only come back in the morning (no... that's not their mother, certainly).
Even though, still vamos would sound indicative.
I wrote "this evening" and it was wrong. If I want to say "this evening we will drink less beer", how do I say it?
Would a better translation into English be "...are going to drink..."? Does Portuguese distinguish between the intentional future "we are going to drink.." and the predictive future "...will drink..."?