Hi Clive, Shall
has two uses - prediction and volition. (See the previous threads on the uses of will or alternatively this article
on my site). It is when you are expressing prediction
can only be used in the 1st as an alternative to will
. So : I will probably see John tomorrow
or I shall probably see John tomorrow
are both OK, but not *He shall probably see John tomorrow.
But volition is another matter. First of all, the precise meanings of shall
are a bit different. Will
is much weaker. So I'll phone you tomorrow
could be glossed as I agree to ...
or I'm willing to phone you tomorrow. Shall
on the other hand actually imposes
the speaker's will on the referent - it has the meaning "I insist that". This is why it's fairly rare - in most situations you can't impose your will on another without creating offence. It may be allowable for God and the Vatican, and mothers have their moments (You shall eat your greens!
) but in general we avoid it, and use it only when what we want to impose is to the benefit of the other person Cinderella you shall go to the ball !
or Don't worry, he shall have it tomorrow.
Or of course in the interrogative Shall I turn the heating up? Shall we go?
By asking the person if they want me to impose my will, I take the possible offence out of the situation - compare I shall do it!
and Shall I do it?.
The other way to lessen the impact is to use the second form of the werb (should)
which makes the imposition hypothetical and therefore less offensive. compare You shall do it!
and You should do it.
These examples also show that shall
can be used in any person - but the imposition remains that of the speaker
, not of the subject : You shall eat your greens!
means "I impose my will to ensure that you eat your greens". It's like must
in this respect.
For this reason your final question isn't possible because it doesn't have a logical meaning - you could command Someone shall now explain it!
meaning I insist that someone explains it!
but the interrogative doesn't work : Do I insist that someone explains it?
doesn't mean what you're trying to say. You need to ask Will someone explain it
- ie Is someone willing to explain it?
Clear ... or worse?