Yes, or 'could', I think, is more common.
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Mister MicawberYes, of course, but that is not what we are speaking of, is it?Right. Just a little off the track, out of interest.
Taka So 'must' of 'must learn' could not only mean a requirement; it could also mean a strong possibility, in certain contextI'm not saying that—and I'm not searching for an example. Maybe that likelihood is 0.