Responsibilities and Obligations
Must and Have to
Must - Strong Personal Obligation
Use 'must' in the positive form to speak about strong personal obligations that you feel are crucial at the moment of speaking.
We must catch up with every other industrialized country in terms of health care.
I must include the indirect benefit I receive.
Have to - Responsibilities
'Have to' is used to indicate responsibilities at work. Use 'have to' to talk about daily responsibilities and obligation in general. 'Have to' is often confused with 'must'. The main difference is that 'have to' expresses obligation to work, family, friends, etc. 'Must' is used to indicate strong personal obligation that is felt at the moment of speaking.
'Have to' differs from other modal forms. 'Have to' is conjugated and followed by the base form.
Positive Form:
The president has to set the tone of debate around public policy.
Negative Form:
We don't have to be ashamed of our interdependency.
Question Form:
Do they have to work through an intermediary or can they work directly with the parent company?
Had to
When speaking in the past, there is only one way to express obligation: 'Had to' We use 'had to' when we speak about past responsibilities and strong personal obligations.
Example:
Bob had to attend an internal benchmarking meeting in order to draft a plan to meet best practices.
Bob had to rally for public support in order to get the bill passed.
Must vs. Have To
'Have to' expresses everyday responsibilities at work, or for family and friends. 'Must' is only used for strong personal obligations.
Example 'Have to' for Responsibilities:
The president has to set the tone of debate around public policy.
Maria has to track the financial output of a hundred different institutions every week.
Example 'Must' for Strong Obligations:
We must catch up with every other industrialized country in terms of health care.
I must include the indirect benefit I receive.
The difference between 'have to' and 'must' in the negative is extreme. 'Not have to' signifies a lack of obligation. 'Mustn't', on the other hand, signifies prohibition. The past form of both 'must' and 'have to' is 'had to'
Example 'Have to' for No Obligation:
We don't have to be ashamed of our interdependency.
A good organization doesn't have to worry about public relations, but rather focuses on community involvement."
Example 'Mustn't' for Prohibition:
The people mustn't be left out of public affairs.
This proposal mustn't be leaked to the press ahead of time.