please can you tell me how to express meaning of "mustn't" (when it is only my opinion) in the past tense?
I mustn't do it today.
I ??????? do it yesterday.
I was not allowed or I was not supposed sounds to me as a someone else's order.
Thanks a lot.
Thank you for your answer.
Yes, I know that, but "don't have to" is not "mustn't" in meaning. So if I want to express "mustn't" in the past tense I can't say "didn't have to".
My understanding has always been this:
"The negative form of 'must' expresses the idea that something is prohibited - this form is very different in meaning than the negative of 'have to'! "
But I might be wrong.
IMPORTANT: The past form of 'have to' and 'must' is 'had to'. Must does not exist in the past." So, the verb "to have" is employed for the past: "Yesterday I had to go to work". How then, are you going to write that it wasn't necessary for you to go to work using the verb "to have"? "I didn't have to go to work yesterday".
Before the auxilliary "did" came into use in English you would have used "Hadn't to".
Presumably, before "did" came into use as an auxiliary, "I didn't go to work yesterday", would have been the rather archaic "I went not to work".
Hmm. I thought the past form of must is must. Like cost.