#english_language ## Must - when we say that it is necessary to do something because *the speaker* decides it is necessary ^53c6a3 - ![[Should and ought to#^8bdd5e]] ## Have got to - when we say that it is necessary to do something because *someone else* or some outside circumstances or authority makes something necessary > I have to see the head teacher - when we talk about a necessity that is characteristic of a person > She has to drink two cups of coffee in the morning before she feels really awake - to derive conclusions in informal speech > Look at all those penguins, there's got to be about a million of them! - we use have to instead of have got to with frequency adverbs (always, never, etc) and in formal English > I often have to work at the weekend to get everything done - with the past simple, we use had to, particularly in questions and negative sentences ## Both - when we say that it is **necessary** to do something, we use must or have (got) to or need to ([[Will and would|will]] have to in the future) > Every animal on the island must / has (got) to be destroyed ##### Notice that have got to is much less formal