1. Unit 8 Do’s and Don’ts
Grammar

2. Table of contents
Have to
Modal auxiliary verbs
Should
Must

3. Have to
Form:
+ : S + have/has + to + infinitive
- : S + have/has + NOT + to + infinitive
? : Do/Does + S + have + to + infinitive ?
Note: past tense of “have” is “had”, with did and didn’t in the question and negative.

4. Have to
Use:
“Have to” expresses strong obligation (coming from “outside”) e.g.: You have to go to school.
“Don’t/Doesn’t” have to expresses absence of obligation, e.g.: We don’t have to wash the dishes tonight.
“Have to” expresses obligation as a habit, while have got to expresses it on a particular occasion.

5. Modal auxiliary verbs These are modal auxiliary verbs:
Can - Could
Must - Shall
Should - Will
Would - May
Can you think of an example for each one?

6. Modal auxiliary verbs Notes: They go with another verb and add meaning
There is no “s” in the third person singular
There is no do/does in the question
There is no don’t/doesn’t in the negative

7. Should Form: Should + infinitive Use:
the forms of should are the same for all persons.
Use:
Should expresses what the speaker think is right or most appropriate. However, it can express just the opinion of them.
Shouldn’t” expresses negative advice.

8. Must Form: Must + infinitive
the forms of must are the same for all persons.
In questions, we should use “have to” instead of “must”

9. Must
Use:
Must expresses strong obligation ( coming from the “inside” of the speaker).
Be careful when using must, you may sound “bossy”
However, must can also express a strong suggestion.

10. Thanks for your attention !
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