| Can anyone tell me what this implies? |
|
It means that there is no past form of
must, such as *
musted.
So if you wish to report "I must go" as indirect speech, you say "I said that I must go", and not "*I said that I musted go."
On the other hand, "I have to go" becomes "I said that I had to go" because
have does change to create the past form.
CJ