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- [Voiceover] Hello grammarians!
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Today we're gonna talk about a class of auxiliary,
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or helper verbs, called the modal verbs.
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These are verbs that have special properties
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and help other verbs.
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But what is modality?
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My fellow grammarian, I am so glad you asked.
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Modality is when we use these verbs to express
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conditions on stuff.
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So we can use these verbs to determine if something
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is likely to happen, or certain to have happened.
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Whether or not something is possible,
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or whether or not we have the ability to do something.
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Whether or not we have the permission to do something.
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And whether or not we have the obligation
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or requirement or need to do something.
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You already know all of these verbs, I promise you.
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You just didn't know this name for them.
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Let's meet the modals.
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Roll call, here we go.
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May, might, must, can,
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could, shall, should,
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will, would.
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Those are the modals.
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So here's what modal verbs can do.
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Thing number one, they agree with everything.
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So you can take any one of these modals
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and you can use any subject in the world
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and it's not gonna change, right?
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You take a word like talk, for instance,
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and you would say I talk,
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Diane talks.
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Right, you add the s.
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But any subject in any sentence is going to take
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the modal verb the same way.
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Let me show you.
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I can do it, you can do it,
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she can do it, they can do it,
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we can do it.
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It's all the same.
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They agree with everything.
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Something else that modals do is actually something
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that they don't do.
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They don't have a to form,
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this is what we call the infinitive.
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So there's no such thing as to may,
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or to could.
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That just doesn't exist.
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So modals don't have infinitives.
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You can't say I want to should.
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That is an illegal operation in English.
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It is ungrammatical.
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It doesn't matter what version of English you speak,
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across all varieties of English you cannot to should.
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And finally, a thing that modal verbs can do
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is indicate modality.
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Which, like we said, establishes conditions.
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So let's take a look at some examples.
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So the word must, right?
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We can use the word must in a couple different ways.
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So, if you imagine a detective looking up from some
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tracks, some muddy bootprints on the floor,
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with her magnifying glass.
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She looks up and she says "He must have gone that way!"
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That detective is using must to express a likelihood,
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a high likelihood.
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This must have happened.
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But if you're at an amusement park
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and the roller coaster you want to ride has a height
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requirement, the sign probably says
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"You must be this tall to ride the Doom-Coaster."
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This is like a necessary condition.
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By a similar token, if you enter someone's house
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and they demand that you take off your shoes,
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they would say "You must remove your shoes."
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Similarly with may, we can use may to express
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a possibility, like saying "It may rain."
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That's something that could possibly happen.
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Or to give someone permission, like
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"You may enter."
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You can use a word like can to express ability.
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You could say "I can eat ten pounds of broccoli!"
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And that's expressing your ability to do a thing.
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We also use modal verbs like this to talk about
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conditions, or stuff that isn't going to happen
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or maybe could happen.
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And so, for example, in this sentence, we would say
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"I would make the bed, but I'm tired."
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Because the possibility exists, however remote,
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that the bed would be made by me,
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but I don't feel like it.
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So I'm using would to offer an excuse,
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I'm saying this could possibly happen, this would happen,
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except for this one other problem,
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which is that I'm sleepy.
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You can also use modal verbs to give advice
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to someone, as in "You shouldn't do that."
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And something that is special to will,
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and, to a lesser extent, shall,
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is that they can form the future.
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Shall used to be a lot more popular,
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and it still is in British English, but less so
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in standard American.
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So would say "He will win the competition."
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Or "He shall win the competition."
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And use of this modal verb will, or shall,
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indicates that that thing that you're talking about
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is happening in the future.
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These verbs are very powerful.
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You should learn how to use them
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and in fact if you can complete the exercises,
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then you will master these tricky verbs.
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You can learn anything.
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David out.