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Video transcript

hello grammarians today we're going to talk about a class of auxiliary or helper verbs called the modal verbs these are verbs that have special properties and help other verbs but what is modality my fellow grammarian I am so glad you asked modality is when we use these verbs to express conditions on stuff so we can use these verbs to determine if something is likely to happen or certain to have happened whether or not something is possible or whether or not we have the ability to do something whether or not we have the permission to do something and whether or not we have the obligation or requirement or need to do something you already know all of these verbs I promise you you just didn't know this name for them let's meet the modal's roll call here we go may might must can could shall should will would those are the modal's so here's what modal verbs can do think number one they agree with everything so you can take any one of these modal's and you can use any subject in the world and it's not going to change right you take a word like talk for instance and you can say I talk Dian talks right you have the S but any subject in any sentence is going to take the modal verb the same way let me show you I can do it you can do it she can do it they can do it we can do it it's all the same they agree with everything something else that modal's do is actually something that they don't do they don't have a to form this is what we call the infinitive so there's no such thing as two Mei or two could that just doesn't exist so modal's don't have infinitives you can't say I want to should it doesn't that is an illegal operation in English it is ungrammatical it doesn't matter what version of English you speak across all varieties of English you cannot to should and finally a thing the modal verbs can do is indicate modality which like we said establishes conditions so let's take a look at some examples so the word must right we can use the word must in a couple of different ways so if you imagine a detective looking up from some tracks some muddy boot prints on the floor with her magnifying glass she looks up and she says he must have gone that way that Detective is saying is using must to express like a likelihood of high likelihood this must have happened but if you're at an amusement park and the roller coaster you want to ride has a height requirement the sign probably says you must be this tall to ride the doomed coaster this is like a necessary condition by a similar token if you enter someone's house and they demand that you take off your shoes they would say you must remove your shoes similarly with May we can use May to express a possibility like saying it may rain that's something that could possibly happen or to give someone permission like you may enter you can use a word like can to express ability you could say I can eat ten pounds of broccoli and that's expressing your ability to do a thing we also use modal verbs like this to talk about conditions or stuff that isn't going to happen or maybe could happen and so it for example in this sentence we would say I would make the bed but I'm tired because the possibility exists however remote that the bed would be made by me but I'll feel like it so I'm using wood to offer an excuse I'm saying this could possibly happen this would happen except for this one other problem which is that I'm sleepy you can also use modal verbs to give advice to someone as in you shouldn't do that and something that is special to will and to a lesser extent shall is that they can form the future shall used to be a lot more popular and it still is in British English but less so in American so you would say he will win the competition or he shall win the competition and use of this modal verb will or shall indicates that that thing that you're talking about is happening in the future these verbs are very powerful you should learn how to use them and in fact if you can complete the exercises then you will master these tricky verbs you can learn anything Dave it out