Unit 8 - Modal Verbs
Modal Verbs
Unit 8 - Modal Verbs
Katie: I have to prepare to teach my classes tomorrow. Pat: What must you do? Katie: I have to create some activities for my students and make copies. Pat: Must you do that tonight? Can you wait until morning? Katie: No, I have to do it tonight. I must finish before 9:00 pm because my favorite show will be on TV. Pat: I hope you don't have to do too much!
Modals (Must/Have To)
Must and have to are modal verbs often used to convey necessity.
- I have to go home now.
- I must arrive by 12.00.
Have to is used for general necessity. For example:
- I have to finish this before 12.00. (I have a general obligation to finish this by 12.00)
Must is used for necessity which we feel personally.
- I must finish this before 12.00. (I have a sense of strong personal responsibility to finish this.)
Must does not have a past form, we have to use have to for the past.
- I had to get up early this morning.
- I must got up early this morning. This is incorrect.
Note that have to inflects like a normal verb, it can have different tenses and uses auxiliary verbs for questions and negatives. For example:
- Do we have to go out tonight?
- You don't have to come with us.
Must doesn't use auxiliary verbs or different tenses.
- Must we go out tonight? (This sounds rather British, I really don't want to go out tonight.)
- We mustn't forget the tickets. (No auxiliary verb "to do", just add not.)
Negative Forms
Don't have to means that something is not necessary, but possible.
- You don't have to come, but you can if you want to.
- We don't have to leave today.
Must not is strong and means that something is prohibited.
- You must not push the red button.
- We mustn't be late.
Must and have to - Certainty
Must and have to can also express certainty.
- This must be the right way.
- This has to be the right way.
Grammar Exercise
Complete the sentences below using must or a form of have to.
Example: You
_____ light a naked flame near the gas pumps.
a) don't have to
b) must not - The answer is: b) must not
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