When would you use the following?
- I have to go the market.
- I must go to the market.
- I need to go to the market.
If I replace 'have' with 'had' would you have any other way to say it? E.g. I had to go the market.
Have to contrasts with must in that it usually expresses an obligation imposed by someone other than the speaker. Had to is the past tense of have to and may be used in cases where a past equivalent of must is required. Need to is used where there is not such a strong obligation, but where completing the action will satisfy a particular requirement.
I'd like to add an important point re: the use of must expressing personal obligation.
The authors of the Longman Grammar of Spoken and Written English argue that
They also add that
cf. Swan 2005 361:4 or Martin Parrott's remark that "many people don't make this distinction" [have to for external obligation and must for internal obligation - Alex B.] (Parrott 2000: 125), see also Quirk et al. 1985: 226 note b.