1. Unit 9 (and 10) Grammar: Modals of Necessity
“have to” and “must”

2. What is a modal? The easy answer: A modal is a special kind of verb!
There is another verb after a modal verb. This verb is like the dictionary form (base form).
Examples:
I must sing.
We have to go.
This must change.
He has to run.

3. What are modals of necessity?
“Have to” and “must”
These tell us something that is necessary

4. Sometimes, “have to” and “must” have similar meaning
“Have to” is usually for conversation.
“Must” is usually for writing.
“Must” is stronger.

5. Some examples … Which would be the most normal choice? Conversation:
I have to go.
I must go.
An academic essay:
People must change their habits to protect the environment.
People have to change their habits to protect the environment.

6. Some examples … Which would be the best choice? Conversation:
I have to go.
I must go.
An academic essay:
People must change their habits to protect the environment.
People have to change their habits to protect the environment.

7. Conjugation of “have to” vs. “must”
I have to We have to
You have to
She has to They have to
Must
I must We must
You must
She must They must
What is the difference between these verbs?

8. “Must”: an unchanging verb!
“Must” is special because it never changes (isn’t that nice?)!
I must study We must study
You must study
He must study They must study
Must CANNOT be used in the past tense. Instead, use “had to”.
WRONG example: We musted go.
CORRECT example: We had to go.

9. Choose “must” or a form of “have to” …
Yesterday, I __(1)__________ do homework all day, so I didn’t have time to go to the store. That means that today, I ___(2)_____ go, because I need to buy milk. I ___(3)_______ buy milk because yesterday my roommate ___(4)__________ take a test, and she got a low score. Now she is sad. Her favorite dessert is chocolate chip cookies, so I ___(5)_______ make them for her today to cheer her up.

10. Choose “must” or a form of “have to” …
Yesterday, I had to do homework all day, so I didn’t have time to go to the store. That means that today, I have to/must go, because I need to buy milk. I have to/must buy milk because yesterday my roommate had to take a test, and she got a low score. Now she is sad. Her favorite dessert is chocolate chip cookies, so I have to/must make them for her today to cheer her up.

11. Practice with a partner
What did you have to do last week? Try to find 5 things you both had to do! (Remember, you can only use “had to” to speak about the past.)
“Last week, we had to …”
What do you have to do this week? Try to find 3 things that you need to do that are different from your partner! (You can use “have to” or “must.”)
“This week, I have to …”
“This week, my partner has to …”
“This week, my partner must …”

12. “Must” and “Have to” in Negative Statements
“Must” and “have to” have different meanings in negative statements!
Think about the differences in each of these sets of sentences:
Parents must not spank their children.
Parents don’t have to spank their children.
Children must not eat all the food.
Children don’t have to eat all the food.
I must not tell my mom the secret.
I don’t have to tell my mom the secret.
Give students a moment to read the sentences and think about the differences between the sentences. Ask students to explain what they understand.

13. “Must” and “Have to” in Negative Statements
What is the difference?
Must not: there is no choice; it is not allowed
Don’t/doesn’t have to: it is not necessary (there is a choice)
Confirm that these concepts form the basic idea of difference between the two forms.

14. Conjugation of “have to” vs. “must” in Negative Statements
I don’t have to We don’t have to
You don’t have to
She doesn’t have to They don’t have to
Must
I must not We must not
You must not
She must not They must not
What are the differences between these verbs?
This is a review of how “have to” is used with the aux. “do” in the negative, while “must,” a true modal, is not. Keep in mind that students may not be familiar with this although the text presents it as review. Adjust the pacing of the lesson accordingly.

15. Practice with a partner ….
Make 3 rules that you think would be important for your child (pretend you have children if you don’t have any!).
Begin your rules this way: My child must not _______.
Have students quickly think of 3 rules with a partner. Have them share the rules with the class. Contrast their meaning with what the meaning would be if “don’t have to” were used instead to illustrate the difference.

16. Practice with a partner …
Now imagine that you are a child again and are describing things you wish you didn’t have to do (things you wish weren’t necessary). Write 3 things that you wished you didn’t have to do as a child.
Begin your sentences this way: When I was a child, I wished I didn’t have to __________.
Have the students complete a similar activity with things they wished they didn’t have to do as a child.

17. Practice: Choose a negative form of “must” or “have to”
Parents ___________ make rules about everything, but some things are very dangerous for children. Parents should teach their children that they ___________ do these things. For example, children __________ always stay out of the kitchen, but they __________ touch a hot oven!
Give students time to work on this individually (probably about 2 minutes). Then review as a class.

18. Practice: Use a negative form of “must” or “have to”
Parents don’t have to make rules about everything, but some things are very dangerous for children. Parents should teach their children that they must not do these things. For example, children don’t have to always stay out of the kitchen, but they must not touch a hot oven!
Give students time to work on this individually (probably about 2 minutes). Then review as a class.