Your sentence is:"Aspetteremo un minuto". The differece is between Present and Future tense.
Italians do often use the present tense to refer to something in the near future. We do it in English too, but less often apparently. I think that "aspettiamo un minuto" is likely to be best translated as "we'll wait a minute" as the literal "we wait a minute" is not likely to be used much as a complete sentence like this one, if at all. That doesn't mean that Duo will accept it of course for fear that we will incorrectly learn that "aspettiamo" is future tense. It could also mean "let's wait a minute" but Duo usually flags the imperative with a ! at the end of the sentence so that is not likely to be their desired translation. This is confirmed by the suggested correct sentence they offer being indicative rather than imperative.
I am Italian and believe this sentence is mostly used as "Let's wait a moment" (and then let's see what happens). Here "a minute" should, of course, not be taken literally, as I belive to be the case in English, too.
• Aspettiamo un minuto.
• [ We wait for a minute. ]
• [ We wait a minute. ]
The above translations were accepted.
Why did you asked "why not"? Did you submit ""We wait a minute and was marked wrong?
:) KK 30AUG2019
I think "we will wait a minute?" sounds better but We wait a minute is like everyone stops and someone announces 'we wait a minute'. Sounds weird. Let's wait a minute" sounds better instead of We in English.
I'm no pro, but that will not be present tense and in your case, you will have to use "aspettare." In the case we've been given, "let's wait a minute" would even be more appropriate
We'll/ we will, is future tense which we haven't done yet. I think at this stage "we wait a minute"is a better translation.
The translation is not likely to be used in English, and, as the present tense is also used to translate a future even in Italian, we will wait a minute is more likely to be the translation.