As far as I've seen, we don't have "shall" in any future tense exercises. I think it's considered obsolete? I hear "shall" used in a very limited amount of phrases like "What shall we do?" etc. and not in any sentence like "He shall go to the movies". The standard way to describe something happening in the future is using "will". I'm not sure though, but I've never really seen "shall" used so often in the last decade :) Not a native speaker though, so would be glad if others comment.
'Shall' is not obsolete in English. It is often used to emphasise something. For example: 'Okay, I shall do that tomorrow'. This is more emphatic than 'Okay, I will do that tomorrow'. Another example: 'I shall get on to that straightaway'. Note that these examples are often used in workplace scenarios, replying to customers or superiors, so they are a more formal use.
It is also used specifically for some questions, as in 'Shall we ...?'; noting that 'Will we ...?' would not be used in these cases.
Thanks! Yes, as I wrote, I basically only hear it in the "What/Where/How shall we ...?" version and similar, when talking about suggestions. Your other examples seem like promises or suggestions, or as you said "workplace" usage.
So then, simply saying "I shall listen to music" as a stand-alone sentence out of context is still OK?
To be honest, my own considerations are:
1) Is it actually totally interchangeable with "will" and will sound OK without context for stand-alone sentences? Sentences in third person? (e.g. "He shall listen to music" without any context...)
2) I'm not sure I have time and energy to go through all exercises and add "shall" to alternative translations, especially if it's not for all sentences but only for some where it sounds natural, and I don't really know which ones since I'm not a native speaker and don't have any around currently.....
Sagitta, 'shall' is not totally interchangeable with will, so I would not advise going through every exercise to change it. Further, this exercise is an odd sentence in itself, but it might be said as a reply to a suggestion from someone and is not incorrect in a grammatical sense. In this case, 'shall' can be used as well as 'will', depending on context and I suggest it is included as an allowed version.
As an addendum to the discussion, shall is used a lot in legal documents when describing a person's responsibilities under the contract, typically as tenant and landlord. This is a very formal use.
Thanks, @DanG943076! (can't reply to your comment, thread limit reached haha)
In that case, I would just not add it anywhere because it's context-dependent, and because it's unclear like that... I would add it in sentences like "Shall we...?" and "What/Where/... shall we...?" if I find them.
Thanks all of you for the comments and help!