I think the key distinction here is that "up" can be used as an adverb in English (indicating a direction, without making a prepositional phrase like "up the stairs"), whereas "on" can only be used like this as a preposition (attached to an object, like "on the table"). I looked up "su" in Italian Wiktionary, which indicates that "su" can also be used as an adverb. It's confusing for Duolingo to put this usage in the "Prepositions" lesson.
Yes, "on" has some adverb meanings, but none of them have to do with being on top of something. To indicate this, you need to follow "on" with an object. Otherwise, it would be read as a phrasal verb: "go on"="continue".
Sorry to make this seem so complicated. I have much admiration for anyone doing these lessons as a non-native English speaker. :-)
My guess would be because Duo is trying to teach us the more common usage of "andare + su."
However, I do agree that your sentence does make sense in English if you wanted to convey something along the lines of "Why don't we go on [the elevator/escalator]?" Perhaps a native speaker can provide more insight on this topic though. :D
I've been around and speaking the sicilian dialect since I was born, Perche non andiamo su to mean why don't we get on is perfectly acceptable, and as far as I know, it is that way in any dialect. Duolingo teaches the type of italian that they teach in Schools and used in academia. For the sake of conversation, there are many different ways to use the prepositions and quite frankly, I think the academic way is a bit unforgiving.
Still, it's good to know and generally if you don't understand the way italians use a certain dialect, you can always fall back on the universally taught academic usages.
Your English sounds pretty good! Don't worry everyone here slips up at times. My English is perfect as it's my mother tongue, but I still got this one wrong. Using a dictionary I mistranslated andiamo as we come rather than the correct we go. Hopefully I'll get the heart when I redo this lesson!
I put 'Why do we not go up?' which duolingo accepted, with an official translation of 'Why don't we go up?' I was wondering if the sentence can mean both. The one I wrote my understanding was that it was a direct question: eg: We should be going up, but for some reason we are not. Why not? The duolingo one translation is more of a suggestion, such as if you were in a shop with two floors and your friend said 'Why don't we go up (to the second floor)?' Is my interpretation incorrect, or can it mean both?
I tried "Why aren't we going up?" -- i.e. we are in an elevator, the doors close, and it stays motionless at the same floor. Duolingo considers this a correct answer, but I wonder whether Italians wouldn't sometimes/often use a different phrase in this situation. Or do you use the same words whether it is an observation or a suggestion?
Native English Speaker, French (and Latin) second languages, Italian tertiary language. Sometimes it helps me to put an Italian phrase into a translator to check later-learned language to earlier learned language to have a sort of 'second opinion'. This probably works best when languages are in the same linguistic tree and you know the root language (here Italian and French are both romance languages family--rooted in Latin). I use an online free-translating site that isn't totally reliable but it may help with connotations. Italian "adiamo su" into french yielded "allons-y". I get a better connotation with the French as an intermediary to english.
nonostante, I gave away a number of lingots to your responses which inspired me to try the translator approach. grazie!
While it is no secret that the hints are known to be off the wall at times :-) this is not one of them. A good trick to remember is to always pick the first hint. Most often it will be correct. Here the first is "up" which is correct. Try it on other sentences it usually works.
Per favore, quale è? Option 1: 'su' means 'up' not 'on' here because if it were 'on' it would have a prepositional object, but 'su' is an adverb here, not a preposition, and doesn't need an object. Option 2: 'su' is a preposition here, not an adverb, and requires a prepositional object, but you can have "understood" prepositional objects that are not stated (as in English: conductor says, "Please get on [the train]."), in which case, there is no way to know whether 'su' means 'up' or 'on' except context. Option 3: Or, when you see 'su' with the verb andare, it usually (always?) means 'up', not 'on'.