Talk:must not

In some varieties must not is used for a negative logical deduction

The negative of the use for deduction in standard British English is formed with could not or cannot:

  He can't have done it by himself
  It couldn't have been the same man

Must used for obligation has no future or past forms (but it does in the sense of deduction)

https://www.eltconcourse.com/training/inservice/modality/central_modal_verbs.html JMGN (talk) 23:35, 18 October 2023 (UTC)