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Hi kids! Today we are going to see the modal verbs have to, don't have to, had to, didn't have to, and must.

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Let's start with the use.

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We use have to or must as infinitive to talk about obligations and things that are necessary to do.

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Must and have to are both used for obligations and are often quite similar.

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they are both followed by the infinitive. Look at the examples. I must go now and I

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have to go now. Is there any difference? Well, we often use must for more personal

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opinions about what is necessary to do and have to for what somebody in

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authority has said it is necessary to do. For example, I must remember to get a

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present for Daisy. That is my opinion. You have to look after their hair regularly.

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That is what dog experts say. Do you have to wear a tie for school? Now we are asking about school

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rules. As you can see there is a slight difference but they are really similar in meaning. But how

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about the negative forms? We have said that the positive forms are very similar in meaning

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but the negative forms are completely different look at examples it says you mustn't run in the

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corridor that is an obligation you have no choice at all you don't have to do this exercise

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there is no obligation to do it you have a choice