HAVE TO & MUST

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Unit 14: THINGS
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Grammar: Must / Mustn’t and Have to
1. We use “have to” or “must” to show
the obligation for doing something.
Ex: a) You have to (must) do your homework.
b) Tomorrow, I have an examination so I have to
(must) study hard tonight.
Sometimes, there’re some differences
between ‘have to’ and ‘must’ obligation


Use ‘must’ to express your own idea, you think it’s
necessary or it’s good for you to do sth
Ex: You look quite tired, you must go to bed early.
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With ‘have to’= is a a rule/ a law/ or sth you are obliged to
do although you don’t want.
Ex: I have to earn money to pay the tuition fees.

2. We can only use “must” to say about the
present and the future.
Ex: a) I must go to school now.
b) Tomorrow, I must go to watch movies with my girlfriend.
c) I had to go to the supermarket yesterday, because there was
nothing in the fridge. (the past simple of must is had to)
“Have to” can be used in all forms.
Ex: a) Last week, Marry had to go abroad. (past)
b) I have had to study hard for a week to get this
good result. (P. Perfect)

c) You have to pay attention to the lecture.

3. Mustn’t and don’t have to are perfectly
different.
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“You mustn’t do something” it means you are not
allowed to do that thing.(prohibition)
Ex: I have a first date with a girl so I mustn’t be late.
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“You don’t have to do something” it means you
don’t need to do that thing, you can do it or not.
Ex: Today is Sunday, I don’t have to study hard.
4. You can use “have got to” instead of
“have to”, so you can say:
a) I’ve got to (have to) work tomorrow.
b) When has Marry got to leave?
Or When does Marry have to leave?
Note: We use do/does/did with “have to” in
the questions and the negative sentences.
a) What do we have to do to get an internet access?
b) I don’t have to go to school on Friday and Sunday.
have & have got
Ai co= Cau vo chu
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Have (in Written E)
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I have (you/we/they have) a house. (positive sentence)
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She/he/it has a house. (positive sentence)
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I don’t have (you/we/they don’t have) a house.
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She /he/ it doesn’t have a house. (negative sentence)
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Do you / I /we/ they have a house?
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Yes, I do. (no, I don’t.)
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Does he have a house? Yes, he does. No, he doesn’t.
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How many sisters do you have? (question)
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I have three sisters.
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How many brothers does she have? (question)
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She has two brothers.
there is / there are
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In positive sent. Singular verb
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There is + a/ an + noun
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There is + some + uncount. Noun
Ex: There is a book (an apple) on the table.
There is some money in my pocket.
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In negative sentence
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There isn’t + a/ an + noun

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There isn’t + any + uncount. Noun
Ex: There isn’t a book (an apple) on the table.
There isn’t any money in my pocket.
In question: Is there a/ an +noun?
Is there any + uncount. noun?
Is there a book /an apple on the table? Yes, there is/ No, there isn’t.
Is there any money in your pocket? Yes, there is.
How much money is there in your pocket? There is a little. (little)
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In positive sent. Plural verb
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There are + some + plural nouns
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There are + cardinal number + plural noun
Ex: There are some books (two apples) on the table.
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In negative sentence
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There aren’t + cardinal number + plural noun
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There aren’t + any +plural noun
Ex: There aren’t two apples on the table.
There aren’t any books in my bag.
In question: Are there cardinal number + plural noun?
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Are there + any +plural noun?
Are there two apples on the table? Yes, there are./ No, there aren’t.
Are there any apples in your bag? Yes, there are.
How many apples are there in your bag? There are a few.

There are two apples.
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A few/ few + count.n
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A little/ little+ uncount.n.
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A few/ a little= some/ several
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There are a few apples left.
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There is a little beer left in the bottle.
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Few/ little= not enough
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There are few apples left. (not enough apples for sb)
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There is little beer left in the bottle.(not enough beer
for sb)
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A very few
5. Exercise
A) Use “you must”, “you mustn’t or “you don’t have to”.
Information for Guests
1 …………… return the keys to reception when you leave.
2 ……………… smoke in the children’s play area.
3 Check out time is 11.00 am, …………… leave your room
before then on your last day.
4 ………………use your mobile phones in the quiet room.
5 The coffee is free. pay for it.
You must

You mustn’t
you must
You mustn’t
You don’t have to
6 If you want to check out late, ………………tell
reception the day before.
7 Towels are available at the swimming pool.
…………………… bring your own.
8 You can use the sauna any time …………………. …
book in advance.
9 The swimming pool is very deep ……………
dive in to it.
10 …………… wear your swimming costume in the
dining room.
You don’t have tos
you must
You mustn’t
you mustn’t
You don’t have to
B) Choose the correct form.
1 The new law means companies must / mustn’t reduce
waste by 10%.
2 The new law says you must / mustn’t smoke
anywhere in or around public buildings.
3 You must / mustn’t throw chemicals away with the
normal rubbish. It’s against the law.
4 I must / mustn’t repair my car. It’s dangerous to drive.
5 I must / mustn’t remember to call Frank and tell him
the meeting’s cancelled.
6 I don’t have to / mustn’t forget to pay my gas bill.

7 We don’t have to / mustn’t pay tax on rubbish.
8 If you must / mustn’t have soft drinks, buy them in
plastic bottles.
9 I must / mustn’t rush. I’m late for class.
10 I can’t talk now. I must / mustn’t finish this work.