Expressing Obligation 5naf

Expressing obligation When it is necessary or obligatory to do something, you should express obligation 1. Obligation in the present have to/must Example  I have to finish my homework before this evening.  I have got to learn English if I wish to live in USA.  I must see the doctor soon because I do/t feel well.  It is obligatory that I stop when the traffic light turns red.  It is necessary that I take a taxi. I’m late.

2. Obligation in the past Had to Example I had to work extra hours to pay my bill. 3. Obligation in the future Example I will have to borrow money.

Things to : 1. The difference between “have to” and “must” is that “have to” indicates that someone has imposed conditions on us. 2. The simple past of “must” is “ had to”. 3. The simple future of “must” is “will have to” 4. “should” also express obligation. But there is a difference must/have to and should “must”/”have to” =100% obligation • “When the traffic light turns red, you must stop”. “should” -50% obligation. It is more an advice than an obligation. • “you look tired. You should have a rest”.

Example of dialog. Policeman : Don’t you know that you must stop when the traffic lights are red? Driver : Sorry, sir. I was so absent-minded that I didn’t pay attention to the traffic lights. Policeman : Well, sir. You’ll have to pay a fine.

Some examples of Expression of Obligation  All students must obey the school rule.  If you want to the exam, you must study hard.  You’re sick. You have to see a doctor.  Your mother said that you had to go home. Some examples of non obligation • I don’t have to go home soon. • The workers must not have lunch at the canteen. • The child does not have to do all the homework by herself.

Must : Usage 1. Must expresses an obligation imposed by the speaker. Example : • You must finish your food. (an obligation put a mother to her son) • I must finish my homework. (It is important I finish my homework) • You must follow me. (you don’t know the way) • We must leave early. (otherwise we will miss the train) 2. We use must to express strong advice. Example : Teacher : You must do your homework or you’ll fail. 3. We usually use “have to” when asking question, NOT “must” Example : Do we have to finish the food? 4. “Musn’t “ expresses prohibtion. It means that something is not allowed or should not be done.

Example : Children must not swim in the deep water. You must not smoke in the gas station. You mustn’t park in the area of “NO PARKING”.

Have to Subject Have to Verb1

……….

Negative

I

Have to

Work

All night

Don’t have

You

Have to

Come

On time

Doesn’t have to

We

Have to

Fill out

A form

“Had to” is the past form of “have to”

They

Have to

Pay

taxes

The negative form of “had to” is “ didn’t have to”

He

Has to

finish

The meal

She

Has to

Study

For her exam

It

Has to

Stay

there

Do/Does

Subject Have to

Verb + …?

Do

I

Have to

Call …?

Do

You

Have to

Go…?

Do

We

Have to

Wear..?

Do

They

Have to

Be …?

Does

He

Have to

Paint ..?

Does

She

Have to

Clear …?

Does

It

Have to

Have …?

Short Answer

Long answer

Yes,

You

do

Yes,

No,

I

don’t

No,

I Have to work all night. I don’t have to…

Yes,

We

do

Yes,

We have to…

No,

They Don’t

No,

No,

He

Doesn’t

No,

They don’t have to… He doesn’t have to

Yee,

She

does

Yes,

She has to …

No,

It

Doesn’t

No,

It doesn’t have to

Usage “Have to” expresses a strong obligation imposed by authority Example You have to stop when the traffic lights turn red. All citizen have to pay taxes. “have to” is more common in spoken English.

Comparison of HAVE TO and MUST Have to

Must

The obligation is imposed by a third person or by rules. It expresses what objectively necessary.

The obligation is mpsed by ‘YOU’ OR THE SPEAKER. It is personal

“Have to” Example • I have to get up early. (because I go to work at 7 a.m) • A policeman has to wear a uniform. (because it is a rule) “Must” Example : I must get up early. ( I will go fishing in the morning.) You must wear a fancy dress to the paerty.

Exercise Fill in the blanks with “have to” 1. Children have to start school when they are five. 2. How old …. you … be to drive in your country? 3. In some countries, every teenager… do military service. 4. ….you … have your parents permission to get married. 5. … everyone …have a driving license?

Note : “Don’t have to” expresses the idea that something is not necessary. Example : You don’t have to come early. We won’t leave till ten.

Comparison between “Don’t have to”with “Mustn’t”

Don’t Have to You don’t need to do it

Mustn’t It is essential that you don’t do it Example : You don’t have Example : You mustn’t use to polish your shoes . They brown polish on your look clean black shoes . It looks awful.

Exercise Fill the blanks with the negative form of “have to”

1. Most vegetable can be eaten row. You …cook them. 2. She …have a heavy lunch. She can have a sandwich if she likes. 3. You … take off your shoes for the dance. 4. I … to give you Susi’s address. You know it already. 5. The boss says we … finish the job today. We can do it tomorrow. 6. You … write her a note. I’ll give her your message.

Exercise Complete the sentence with don’t have, doesn’t have to, mustn’t, or have to 1. 2. 3. 4. 5. 6. 7. 8. 9.

Kirsten, you … say such things. That is very unkind of you. In the army, soldiers … wear uniform. In most schools, teachers … wear uniform. Mrs. Garcia is very rich … She works for a living. The food is too hot. You … eat it yet. Wait a few second for it to cool. I …. get early, because I have an appointment with the mayor at 8:00. Children … play with matches. It is dangerous. I finish all of my homework this afternoon. I … do anything tonight. I …. Study tonight I have an exam tomorrow.

Exercise Match the following statement 1. The show will start in few minute

a. I must clean the house

2. I have guests today

b. I must buy some eggs.

3. You are sick

c. You must hand in your paper now.

4. The road has many sharp curves.

d. Must hurry

5. I want to make an omelet.

e. You must drive carefully

6. This book is overdue.

f. I must find my suitcase.

7. He has a high blood pressure

g. You must rest.

8. I’m going on a trip.

h. You must lost weight and eat cholesterol free food.

9. Your time Is up.

i. I must return it to the library.

Complete the sentence using You + mustn’t and the verbs in the box

You

Must Must not

Help Talk Smoke Buy Walk Be Fasten Cheat See Go to bed

Con’d 1. _________ the doctor if you feel sick. 2. _________ a present for mother’s day 3. _________ early so you can get up early. 4. _________ on the grass. 5. _________ loudly in the cinema. 6. ________ in a closed room. 7. ________ others 8. ________ your seat belt when you are driving. 9. __________ in exams. 10. _________ polite to old people.

Should Subject

Should

Verb

Object

Adverb

I

Should

Pay

The bill

Today

Negative

You

Should

Go

Home Now

Should not

He

Should

Come

Early

Negative contraction =

Everyone

Should

Be

Here by four

Shouldn’t

It

Should

Be

enough

We

Should

Save

They

Should

Work

The students

Should

Finish

Water Faster

Their work

Should Should Should Should Should Should Should Should

Subject I You He She It We They

Verb See Use Read Write Have Pay Make

………? …...? ……? ……? ……? ……? ……? ……?

Short Answer Yes, you should No, I shouldn’t Yes, he should Yes, she should No, it shouldn’t No, we shouldn’t No, they shouldn’t

Long Answer Yes, you should see … No, you shouldn’t use… Yes, he should read …. Yes, she should write … No, it shouldn’t have …. No, we shouldn’t pay … No, they shouldn’t make …

Usage We do not change the form of the verb when we use should. We use the base form of the verb. Example I should take some medicine. She should do her homework now. He shouldn’t be late for the class. We should help father. They shouldn’t tell lies. You should visit your grandparents.

1. Should express advice. The speaker state an opinion or advice regarding what should or should not be done. Example • You should study if you want to the exam. ( It’s good for you to study) • He should not eat so much. (It’s bad for him to eat too much) • Scott and Zaldo should go on holiday. They worked very hard last year. ( It will be good for them to go on holiday) • Carol and Ann shouldn’t go to the movies. They have an exam tomorrow, (It’s not good for then to go to the movie)

Comparison of Should and Must Should

Must

It is idea to do something but you do not have to do it. You are advised to do this but you have other alternatives.

It is important to do something It is very necessary. You do not have any other alternatives.

Example Should • I should pay the bill today. (I can pay it the day after tomorrow as well.) • You should take your umbrella ( it is not raining, but it is cloudy. It could rain today.) • He should buy an extra key for the door. (we may need it)

Example Must  I must pay the bill today. ( it is the last day to pay it.) 



You must take your umbrella ( it is raining outside or it will definitely rain.) We must buy a new key (we have lost the key)

Go on diet go to the bank See a dentist hurry go to a parking lot Take it to the mechanic Get car insurance Call the police

Respond A. Use “should” and the expression in the box. 1. A : I don’t have any money. B : _____________ 2. A : I have toothache. B : ______________ 3. A : I’m having a problem with my cat. B : ____________________ 4. A : He is overweight B : ___________________ 5. A : I can’t find a place to park my car. B : ___________________ 6. A : I just bought a car B : _________________________ 7. A : I’m late B : ________________ 8. A Look! Two men are fighting outside, B : ____________________________

Read the situation, and make sentences using the verbs in parenthesis and should and should not

1. You have an exam tomorrow. (today/go out/tonight) 2. Calvin has an important meeting. (wear a suit/jeans) 3. Carol has an appointment at 7 a,m (go to bed early/ watch TV tonight) 4. Your neighbor is in hospital. (visit) 5. A : I have a headache. (take some medicine/read in the dark) B : You ________________ 6. Paul wants to go to Japan next week.( book his fight)