Must and Have to for Obligation
In English, we use must for formal or written rules of obligation.
- We must wear a suit in the school.
- You must obey the rules in the firm.
- You must listen to the teacher in the class.
- You must finish this job tomorrow.
- He must come to the interview.
- I must warn you not to speak too loud.
Notice that the usage of “must” is the same for all subjects (he, she, you, etc.).
For less formal situations, we use have to for obligations. Sometimes, the “to” is dropped after the verb “have”.
- I have to go home now because I’m tired.
- You have to wear your seatbelt while in the car.
- She has to leave now.
- He has to enroll for the university tomorrow.
For subjects “she,” “he,” and “it,” we use “has” following the same rule.