This document provides an overview of modal verbs used to express necessity and obligation in English. It begins with definitions of modals, necessity, and obligation. It then discusses specific modals - must, have to, and have got to. It provides examples of how to use these modals to talk about rules, strong advice, and things that are necessary to do. It also discusses how to form negatives and questions. The document concludes with exercises for learners to practice using these modals in sentences.

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ModalsofNecessity&
Obligation
CLBlevel 5+
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3. Modals – A quick review
What are modals…?
Modals, or modal verbs, are auxiliary or “helping” verbs. They come
before the main verb to give it more meaning.
English modal verbs include:
must, shall, will, should, would, can, could, may, and might.
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4. Modals – A quick review
What are modals…?
Modals are always followed by a base verb.
The base form of a verb is a verb without an ending, like “ed”, “ing” or
“s”.
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5. Modals – A quick review
“We use them to do things like talk about ability, ask permission, and
make requests and offers:
I can't swim. ABILITY
May I ask a question? PERMISSION
Could I have some tea, please?” REQUEST
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6. Modals – Necessity & Obligation
We also use modals to talk about necessity and obligation. These
include “must, have to and have got to.” These modals are used to express
rules or strong advice.
Necessity (noun) – the need for something, something you need
Obligation (noun) – something you do because you feel you must or
have to.
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7. Modals of Obligation
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Obligations:
We use must or have / has to to say that it is necessary to do something:
You must stop at a red light.
Everyone has to bring something to eat.
Must is the strongest modal and is most commonly used in writing.
Have to (or has to) is more common in spoken English.

8. Modals of Obligation & Necessity
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Let’s have a look:
https://www.youtube.com/watch?v=POFfLs0Uaio&ab_channel=OxfordOnline
English

9. Modals of Obligation & Necessity
Some examples: Note the modal and the base verb in each
sentence.
I must study today.
I have to buy a new winter coat.
She must get to work on time today.
They have to pack for the trip to Mexico.
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10. Modals of Obligation & Necessity
MUST:
• is the strongest of these modals.
• is used most often in written English
• can be used in the negative (must not), but is
rarely used for forming questions.
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11. Modals of Obligation & Necessity
MUST (Examples):
He must be on time for work.
You must do your English homework.
I must text her this morning.
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12. Modals of Obligation & Necessity
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MUST (Examples - negative):
We use mustn’t / must not to say that it is necessary to not do something.
You mustn’t / must not make any noise in the library.
You mustn’t / must not say anything to her. It's a surprise.

13. Modals of Obligation & Necessity
MUST (More Examples - negative):
He must not be late for work.
You must not forget your English homework.
I must not text her too early.
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14. Modals of Obligation & Necessity
MUST (Examples - Questions):
***Using “must” for questions is formal and uncommon.
Must I cook again tonight?
Must you talk so loudly?
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15. Modals of Obligation & Necessity
HAVE TO:
• is the most common of these modals.
• is used most often in spoken English.
• is useful for forming questions and negatives.
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16. Modals of Obligation & Necessity
HAVE/HAS TO (Examples):
She has to cook dinner this evening.
I have to mail that letter.
They have to move before the end of the month.
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17. Modals of Obligation & Necessity
HAVE TO – Negatives
To form the negative, we add “don’t” or doesn’t”
(depending on the subject) to “have to”.
She doesn’t have to cook dinner this evening.
I don’t have to mail that letter.
They don’t have to move before the end of the
month.
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18. Modals of Obligation & Necessity
HAVE GOT TO:
• is most common in informal speech.
• is never used for forming questions and negatives.
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19. Modals of Obligation & Necessity
HAVE/HAS GOT TO (Examples):
I have got to get groceries tonight.
He has got to stop talking so much.
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20. Modals of Obligation & Necessity
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IMPORTANT NOTE - Negatives
Don’t have to and must not have very different meanings in English.
Must not (mustn’t) expresses strong obligation—you cannot do
something.
You must not be late for work again.
Don’t have to means you can choose not to do something, but you can
do it if you want to.
You don’t have to come in early this morning.

21. Modals of Obligation & Necessity
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IMPORTANT NOTE - Negatives
Can / cannot / can’t are modals of ability and permission, but in the
negative, cannot and can’t can also express that something is forbidden
or must not be done.
We can call cannot or can’t a modal of necessity/obligation with a very
similar meaning to must not.
You can’t be late for work again,.

22. Modals of Obligation & Necessity
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PRONUNCIATION NOTES - Reductions
In spoken English, native English speakers often reduce modals.
This means that some sounds change or disappear when words are spoken
together. This is also called a “reduction.”
Listen to how the following sentences sound:

23. Modals of Obligation & Necessity
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PRONUNCIATION NOTES:
source: Ellii.com

24. Modals of Obligation & Necessity
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PRONUNCIATION NOTES:
Even though the pronunciation changes, the spelling (in written English) does not.

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Let’spractice!
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26. Rewrite the sentences with “must” or “has/have to”:
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1. We must arrive to class on time.

27. Rewrite the sentences with “must” or “has/have to”:
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1. We have to arrive to class on time.

28. Rewrite the sentences with “must” or “has/have to”:
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2. I have to study harder in English class.

29. Rewrite the sentences with “must” or “has/have to”:
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2. I must study harder in English class.

30. Rewrite the sentences with “must” or “has/have to”:
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3. She has to return the library book today.

31. Rewrite the sentences with “must” or “has/have to”:
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3. She must return the library book today.

32. Rewrite the sentences with “must” or “has/have to”:
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4. My friend has to get more sleep at night.

33. Rewrite the sentences with “must” or “has/have to”:
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4. My friend must get more sleep at night.

34. Unscramble the sentences:
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1. wear / must / business attire / at the office/ you

35. Unscramble the sentences:
35
1. wear / must / business attire / at the office/ you
You must wear business attire at the office.

36. Unscramble the sentences:
36
2. 1 / the schedule / every morning / have to / check

37. Unscramble the sentences:
37
2. I / the schedule / every morning / have to / check
I have to check the schedule every morning.

38. Unscramble the sentences:
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3. get to know / you / the bus schedule / must

39. Unscramble the sentences:
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3. get to know / you / the bus schedule / must
You must get to know the bus schedule.

40. Unscramble the sentences:
40
4. he / Does / have to / come / early/ work / to / ?

41. Unscramble the sentences:
41
4. he / Does / have to / come / early/ work / to / ?
Does he have to come to work early?

42. Unscramble the sentences:
42
5. must / to / come / you / not / late / work

43. Unscramble the sentences:
43
5. must / to / come / you / not / late / work
You must not come late to work.

44. Unscramble the sentences:
44
6. your computer / home / at night / cannot / take / you

45. Unscramble the sentences:
45
6. your computer / home / at night / cannot / take / you
You cannot take your computer home at night.

46. Unscramble the sentences:
46
7. clean up / have got to / your work station / before you leave /
You

47. Unscramble the sentences:
47
7. clean up / have got to / your work station / before you leave /
You
You have got to clean up your work station before you
leave.

48. Use a modal of necessity or obligation (must / have to / has to) to
complete the sentences:
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1. I _________________ get to work on time.

49. Use a modal of necessity or obligation (must / have to / has to) to
complete the sentences:
49
1. I must get to work on time.

50. Use a modal of necessity or obligation (must / have to / has to) to
complete the sentences:
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2. Do I ________________ do my English homework?

51. Use a modal of necessity or obligation (must / have to / has to) to
complete the sentences:
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2. Do I have to do my English homework?

52. Use a modal of necessity or obligation (must / have to / has to) to
complete the sentences:
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3. She __________________ not drive the car. She doesn’t have a
license.

53. Use a modal of necessity or obligation (must / have to / has to) to
complete the sentences:
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3. She must not drive the car. She doesn’t have a license.

54. Use a modal of necessity or obligation (must / have to / has to) to
complete the sentences:
54
4. I _______________________ get groceries on the way home from
work. My refrigerator is empty!

55. Use a modal of necessity or obligation (must / have to / has to) to
complete the sentences:
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4. I have to get groceries on the way home from work. My
refrigerator is empty!

56. Use a modal of necessity or obligation (must / have to / has to) to
complete the sentences:
56
5. He _______________ not drink so much coffee! He will never
sleep tonight.

57. Use a modal of necessity or obligation (must / have to / has to) to
complete the sentences:
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5. He must not drink so much coffee! He will never sleep
tonight.

58. Use a modal of necessity or obligation (must / have to / has to) to
complete the sentences:
58
6. I _______________ give you directions to my house if you are
coming to the party on Saturday.

59. Use a modal of necessity or obligation (must / have to / has to) to
complete the sentences:
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6. I have to give you directions to my house if you are coming
to the party on Saturday.

60. Fill in the blanks with must not or don’t / doesn’t have to and the
verb.
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Example:
1. I __________________ (forget) to lock up when I leave.
I must not forget to lock up when I leave.

61. Fill in the blanks with must not or don’t / doesn’t have to and the
verb.
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2. My father _____________________ (eat) junk food every day because it’s
bad for his heart.

62. Fill in the blanks with must not or don’t / doesn’t have to and the
verb.
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2. My father must not eat junk food every day because it’s bad for his
heart.

63. Fill in the blanks with must not or don’t / doesn’t have to and the
verb.
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3. You ________________ (read) the entire article if you don’t want to.

64. Fill in the blanks with must not or don’t / doesn’t have to and the
verb.
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3. You don’t have to read the entire article if you don’t want to.

65. Fill in the blanks with must not or don’t / doesn’t have to and the
verb.
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4. She’s lucky. She _________________ (finish) her homework before going
out tonight.

66. Fill in the blanks with must not or don’t / doesn’t have to and the
verb.
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4. She’s lucky. She doesn’t have to finish her homework before going
out tonight.

67. Fill in the blanks with must not or don’t / doesn’t have to and the
verb.
67
5. We _____________________ (plan) our trip right now. We can wait for
another time.

68. Fill in the blanks with must not or don’t / doesn’t have to and the
verb.
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5. We don’t have to plan our trip right now. We can wait for another
time.

69. Fill in the blanks with must not or don’t / doesn’t have to and the
verb.
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6. We __________________ (be) late for the morning meeting.

70. Fill in the blanks with must not or don’t / doesn’t have to and the
verb.
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6. We must not be late for the morning meeting.

71. Fill in the blanks with must not or don’t / doesn’t have to and the
verb.
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7. You ________________ (apologize). It is not your fault.

72. Fill in the blanks with must not or don’t / doesn’t have to and the
verb.
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7. You don’t have to apologize. It is not your fault.

73. Questions?
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74. Homework:
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1. Think about some traditions in your country.
2. Write 3 sentences telling me about them.
3. Use the modals must, must not, can’t, have to, don’t have to, and / or have
got to in your sentences.

75. HOMEWORK: The details
1. Submit your homework to Lori on Skype: live:loramoren
2. I will correct it and provide feedback.

76. Sources:
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https://learnenglish.britishcouncil.org/grammar/english-grammar-
reference/modal-verbs
https://www.perfect-english-grammar.com/modal-verbs-of-obligation.html
https://app.ellii.com/lesson/2019-modals-of-necessity-obligation
https://continuingstudies.uvic.ca/elc/studyzone/330/grammar/330-modals-
necessity/#:~:text=Let's%20read%20about%20how%20to,is%20most%20com
mon%20in%20writing.

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