What is the difference between "must" and "have to"?

[Solovey]

Test No. incompl/elem-7 "Modals", question 5

Do you ......... clean the house every day or every week?

(a) must
(b) have
(c) have to

Test No. incompl/elem-7 "Modals", answer 5

Do you have to clean the house every day or every week?

Correct answer: (c) have to

Your answer was: incorrect
Do you must clean the house every day or every week?
_________________________

Why it is so?

Solovey

[Torsten]

When we use the modal verb must in a question we don't need the auxiliary verb (help verb) do/does.

For example:
Must you speak so loudly? Can't you see I'm working?

TOEIC listening, talks: Voice mail announcement

[Lisa_Mard]

"must" can not use "do"
and
"have to" can use "do"

Am i right??

[Torsten]

Yes Lisa, you are right.

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[Tiffanyenglish]

Hi Torsten,

In test #7, I got 9 out 10 because I carelessly missed answering #8. Although I answered all of nine questions correctly, but I can't explain why. It sounded right to me. That's how I would normally speak. I would like to learn more about the modals. Please let know where I can learn more about it. I don't have a specific question but would like to know more about other modals. Thank you.

Tiffany

[Lanhuong]

Can you show me the differences between " must" and " have to"?
Thanks for your help!

[Torsten]

Sure, please read this: "must" vs "have to"

And this: use 'must or have to'

And this: Modal verbs: must/have to

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[Sroth]

Dear Torsten,

I did the exercises on elementary 7,I got correct scores 9 out of 10 .Since ,I confused to use Have instead of Had .
I also read explanation of a few sentences thoughly concerning a using of ouxilaries verbs Must and Have to .In your phrases have posted ,its saying that in the question it doesn't need "do" using with Must ,except " Have to" .
Now I'm sure to undrestand them.
I have to show my appreciation on your clear explanation.

Regarsd
savath

[Bheemaiah]

Dear Torsten,

In test #7, I got 8 out 10. Although I answered all of eight questions correctly, but I can't explain why. It sounded right to me. That's how I would normally speak. I would like to learn more about the modals. Please let know where I can learn more about it. and also my confidence level is very low can you please suggest me how to improve.........

Regards,
Bheemaiah

[Sroth]

Dear Torsten,

I'm very gratitude for your admanistration of the Must and Have to or Have got to in detail.When I clicked on the HERE, it's shown the ways to use them including many examples that make me sense of it furthermore.
As my notice on that points,the different thing between Must and Have to are that Must can not be used with the Auxelaries verb do or does for interogative, but Have to can be.Must expresses the decision is necesary, but it has not the form of future and past.The past form of the Must is Had to.

Best regards

Savath

[AlinowalI]

must in the question form dont need auxilary verb

[Alushilindi]

yes, i understood you. thannks