“Must” and “have to” are both modal verbs that can express necessity or obligation, but they are used slightly differently in terms of strength, formality, and the type of necessity they convey.

– “Must” typically expresses strong personal obligation or necessity, often indicating a conclusion based on the speaker’s judgment or opinion. It often implies a form of internal obligation or a rule that is self-imposed or perceived as essential. For example: “I must finish this report by tomorrow.”

– “Have to,” on the other hand, is often used to express external necessity or obligation. It implies that an external rule, authority, obligation, or condition is requiring the action. It denotes a sense of duty or compulsion rather than personal judgment. For example: “I have to attend the meeting.”

– In terms of strength and formality, “must” is generally considered stronger and more formal than “have to.” “Must” can sometimes be seen as more emphatic or authoritative, especially in written communication or formal contexts. On the other hand, “have to” is often perceived as less forceful and more common in everyday language to indicate regular obligations or requirements.

– However, in some contexts, such as when expressing rules, regulations, or laws, “have to” can be as strong or even stronger than “must.” For instance, “You have to wear a helmet when riding a motorcycle” implies a compulsory rule that must be followed, similar to the use of “