Thank you! I still cannot wrap my head around it but I think I got the twist. (As with some other quirks of the italian language structure I hope that the next time I stumble upon it it will just seem natural. My brain seems to adapt itself to the language overnight sometimes.. :) )
Why all the complaints? This is perfectly normal Italian. If it is difficult to come up with an exact English translation then just learn the Italian in its context and get the feel of it. After a while you will not only understand it, you will feel comfortable with it, that is until some English speaker asks you what it means. At first think either "then of course, certainly" or "in that case" but try not to translate. Just hear the Italian and think it in the Italian. Another example: "un gatto" at first you think is "a cat" but after a while "un gatto" is that furry, cuddly, sometimes nasty animal called "un gatto". You don't need to think "cat" at all.
This is good advice, but not really consistent with how Duolingo is trying to teach, i.e. all about associating Italian words and expressions with English ones. I think in this case, the complaints are coming from the sentence's poor rendering in English rather than any issues with the Italian sentence. I like that they're trying to teach us 'sì che', but 'of course' really isn't a good way of translating it.
But they all mean the same thing, right? So that shows that you understand what the Italian means. Great! That's what counts. Don't forget what you are here for. Discussing all the possible local variations of English won't help you learn any more Italian. Just accept the translation DL prefers and move on.
If the Italian meaning were ambiguous then different possible English translations could be discussed profitably.
that's inconsequential to the argument. the translation from italian should reflect how the second language expresses an idea; and vice versa. to translate from english 'to go in' it would be correct to use 'entrare'; but from italian 'to go in' and 'to enter' would be synonymous and perfectly good english.
The main problem of this whole lesson is the meaning of this verb tense 'will have entered' 'will have learned' 'will have gone' etc. I don't see any difference in using it in 'will enter' 'will learn' 'will go' in english Simple Future Tense. Lack of context is obvious to be able to catch the difference between 'will have learned' and 'will learn' in italian. Seems DL teaches us how to make future tense in several ways but not when to use each other. That is crazy way to learn somebody anything... simply, this DL unit has no sense. I feel like a parrot. Might be I'm not alone here...