Fill in the blanks as appropriate.
1. Have to and must express obligation. Must suggests that the authority comes from the speaker, whereas have to conveys that it is not imposed by the speaker, but by the circumstances. Nonetheless, must often replaces have to to indicate that, even though the speaker has nothing to do with it, he or she agrees with it. Have a look at the examples below:
You must be at home before it gets dark. (I am your mother or your father, and want you to obey me.)
I have to get up at five o'clock in the morning to go to work. (The idea of getting up so early does not appeal to me at all, but if I do not work, I do not make a living.)
You must/have to follow the doctor's advice.
a I __________ go home on foot: no means of transport can take me there.
b He __________ work twelve hours a day to maintain his family.
c We __________ leave now. We've got lots of things to do.
d She __________ be here by midnight, or else I'll punish her.
e You __________ give up smoking. You're always coughing!
The opposite of must
is need not
; of have to
, do not have to
. Still, do not have to
may be used instead of need not
You needn't/don't have to read all the book. The first two chapters will be enough.
I don't have to get up early tomorrow, as it is Sunday.
He __________ (not) work. His wife is very rich.
You __________ (not) take me there. My mother can do it.
You __________ (not) buy us a present. You're very short of money.
You __________ (not) take your car. You can go in mine.
They __________ (not) come if they don't want to.
3. Must and need not refer to the present or future only. Have to and not have to are necessary when must and need not are not possible.
We must hurry: it is getting late. (present)
We must visit our parents tomorrow. (future)
We will have to visit our parents tomorrow. (future » external authority)
We had to hurry, as it was getting late. (past)
He needn't pay me for that. (present)
She needn't come tomorrow. (future)
He didn't have to pay me for that. (past)
She didn't have to come the next day. (past)
a I know that yesterday you __________ be at home before it got dark.
b We __________ (not) go to school yesterday, so we went for a picnic.
c I __________ study all night long yesterday because I wanted to get top marks.
d We __________ (not) ask their advice, since Martha was there and helped us.
e Our troops __________ retreat. Our soldiers are falling like flies.
4. Must not
is used to express prohibition or to imply that it is better to avoid something because of the bad consequences of it:
You mustn't eat all that. It's very spicy and hot.
You must not overtake. There is a continuous line here.
You __________ (not) drive so fast. This road is very dangerous.
You __________ (not) drink more. You have to drive.
You __________ (not) arrive late for your interview.
They __________ (not) make any comments about this.
She __________ (not) forget to switch the light off when she leaves.
express advice, but must
You should cut down your expenses.
You must visit Barcelona. It's the best city in the world.
You __________ see this film. It's extremely good.
You __________ tell them what happened.
He __________ take evening classes. They will do him some good.
You __________ listen to this record. You'll love it.
You __________ come to the party with us. You'll enjoy it very much.
6. Need not have + past particle
means that we did something unnecessary:
You needn't have taken a bus. You could have gone in my car.
You __________ (not) have brought anything. There is plenty of food in the house.
We __________ (not) have sent them a letter. They will be here tomorrow.
He __________ (not) have paid for the ticket. I have one spare ticket.
She __________ (not) have bought that book. I could have lent her mine.
They __________ (not) have read the whole novel. They only had to read the first three chapters.
When there is enough evidence to believe that something is true, we use must
. The opposite of must
They must be filthy rich because they have their private jet.
They cannot/can't have a Rolls-Royce. They are very poor.
You must have had a great time in Eivissa.
You cannot/can't/could not/couldn't have seen a vampire last night. Vampires don't exist!
There __________ be a mistake in the bill. It __________ (not) cost so much. You told me it was very cheap.
They __________ (not) have fired him. He's been working for them for over twenty years.
You __________ (not) be serious! You __________ be joking!
You __________ (not) have seen him smoking. He detests it.
If you haven't eaten anything since yesterday, you __________ be very hungry.
8. Revision exercise.
My father __________ work overtime to support us when we were children.
We __________ help our parents when they were ill.
You __________ (not) have bought any roses. There are lots in the garden.
You __________ (not) worry about this illness. It's under control.
He __________ come last night. We needed him.
You __________ (not) swim in this river. Its water is heavily polluted.
We arrived here so late that we __________ take a taxi.
I know that you __________ stay at home helping your mother yesterday, but you could have phoned me
to tell me you weren't coming.
We __________ leave at once, or else we'll get there late.
She __________ (not) have failed her exam. She studied very hard.
What they say __________ (not) be true. They __________ be wrong.
You __________ (not) park the car in the car park. I'll be using it this afternoon.
You __________ (not) have gone all that way on foot. You could have caught a bus!
I'm afraid to tell you that you __________ repeat the year. You've got the poorest marks in the class.
We __________ (not) make the beds. The maid will make them.
You __________ (not) drink and drive. It's a very dangerous combination.
She __________ (not) come to work yesterday, so she stayed at home.
I __________ take that train, otherwise I won't get there in time for the meeting.
She __________ pay us a visit the next time she comes to town. We insist on it.
You __________ take some exercise. You're putting on weight.
This plant __________ be watered every evening, or it'll wither.
We had an accident, so we __________ call a breakdown truck.
You __________ (not) ring up the police, or we'll be put away for theft.
You __________ slow down. Your health is very poor. Nevertheless, it is up to you.
You __________ (not) help us. We don't need any help.
We got a puncture and __________ change the wheel.