must

'Must' is a fundamental modal auxiliary verb in English. Unlike standard verbs, it does not change form; it remains 'must' regardless of the subject (I, you, he, she, it, we, they). It is primarily used to indicate obligation or necessity. Usage Patterns: When expressing obligation, 'must' implies that the speaker is imposing the rule or that the situation is unavoidable. It is followed by the base form of the main verb without 'to' (e.g., 'You must go'). In negative form, 'must not' (or 'mustn't') expresses prohibition, indicating that something is strictly forbidden. Beyond obligation, 'must' is used for logical deduction, such as 'He must be tired,' meaning the speaker is almost certain this is true based on evidence. Common Contexts: You will encounter 'must' in formal instructions, legal documents, and rules, such as 'Passengers must remain seated.' In conversation, it is used to give strong advice, like 'You must try this cake; it is delicious.' It is also common in deductive reasoning when observing facts. Similar Words Comparison: 'Must' is often compared to 'have to.' While they are synonyms, 'must' usually reflects the speaker's personal authority or internal feeling of necessity, whereas 'have to' often refers to external rules or circumstances. Furthermore, 'should' is a weaker version of 'must,' used for suggestions rather than absolute requirements. Understanding these nuances helps in selecting the right level of urgency in your communication.