Advanced Grammar for IELTS Modal verbs (2): must, should, ought to, have to, need to – Diagnose Test, Grammar Explanation & Practice Exercises

Advanced Grammar for IELTS Modal Verbs (2): Mastering modal verbs like must, should, ought to, have to, and need to is crucial for achieving a high IELTS band score. This guide provides a diagnostic test, clear IELTS grammar explanations, and practice exercises to help you understand and use these advanced structures effectively in your IELTS writing and IELTS speaking tasks.

Diagnostic Test: Modal verbs (2): must, should, have to, ought to, need to

Example:

1. To must/ Having to listen to hip-hop music all evening is my idea of torture!
2. The landlord ought to/ ought to have taken his responsibilities more seriously.
3. This company is awful to work for. We must / have to account for every minute of the day.
4. Do you know if we must/ have to have visas for the Caribbean?
5. The newspaper shouldn’t have/ mustn’t have printed the rumor without concrete evidence.
6. What a state my shoes are in! They need/ must be repairing.
7. We have to/ are supposed to put our bags in the lockers, but most people take them into the gym.
8. We couldn’t go/ mustn’t have gone into the disco because we were too young.
9. Polite notice: children do not have to/ are not allowed to play on the grass.
10. This offer is not open to current employees. Participants must not have/ need not have been employed by the company in the last four years.
11. We needn’t / needn’t have booked the tickets in advance; there was plenty left.
12. With our new range of hair products, you mustn’t/don’t have to spend hours caring for your hair.
13. There wasn’t anyone on the nightclub door so we didn’t need to show/needn’t have shown proof of our age.
14. As we’re getting a lodger, we’d better / better to have some more keys cut.
15. Our advice is that even people as young as twenty-five should / must consider a personal pension.
16. You won’t have to/ had better not tell Shirley what you saw – it will only upset her and she’ll blame you.
17. The ground’s soaking outside – it must rain/ be raining quite heavily.
18. If you bring your receipt, there shouldn’t/ mustn’t be any difficulty with a refund.
19. Lewis must have/ should have been training very hard to develop muscles like that!
20. I walked into the showroom and saw the car, and I knew I had to have / must have had it.

Grammar Explanation: Modal verbs (2): must, should, ought to, have to, need to

Obligation and Necessity

Form

Must, should and ought to are modal verbs (unlike the need to and have to). They do not change their form in the present tense, nor do they have a past tense or a future form with a will, nor infinitive or participle forms. As an alternative to must or when we can’t use must (e.g. to refer to the past), we usually use have to:

• Past: The staff and students at the university had to evacuate the campus.
• Future: The Council must/ will have to find ways of cutting costs next year.
• Infinitive: It’s difficult to have to stand by and watch your child in pain.
• Participle: Having to listen to hip-hop music all evening is my idea of torture!

We can express a past meaning of should and ought to by using a modal perfect:

• They really should/ ought to have consulted their shareholders first.

The need can be used as a modal verb (without to), usually in negatives and questions:

• Need you shout so? I’m right next to you!
• We needn’t bother making the bed. The maid will do it.

As an alternative to needing, we can use need to or have to:

Do you need to/have to shout so?

We don’t need to I have to bother making the bed.

• We can use must, have to and need to with a passive phrase:
• Democracy must/has to be seen to work.
• Pulses need to be cooked thoroughly to eradicate the toxins in them.

Obligation

We usually express obligation in English with must or have to:

• You must arrive in good time for the meeting tomorrow. The MD will be there.
• Everyone has to register their name and address in order to be able to vote.

The difference in meaning between have to and must be fine and often depends on whether or not the speaker sees the obligation as one they are imposing. We use to have to to express an obligation we see as outside our control, eg. rules imposed by an authority:

• Students have to wear school uniforms in the sixth form.

We often use must to express an obligation imposed by the speaker:

• I must get up earlier –  I waste so much time in the mornings.

Must is commonly used for the following situations:

• To give a strong personal opinion: I believe people must vote at elections.
• To impose an obligation on oneself: I really must lose some weight.
• To give instructions: The electricity must always be switched off before repairs are attempted. (In giving instructions, a must is often used with a passive verb.)

Note: However, must express a strong obligation and we do not often use it in face-to-face conversation as it can seem impolite and often inappropriate.

We often use should and ought to as an alternative to must as they express a subjective (often moral) obligation felt by the speaker, but the obligation is weaker than with must:

• You should treat your neighbours with more respect.

It is possible to use need to to express external obligation, particularly in the future:

• We’ll need to get our visas sorted out or we won’t be able to stopover in the States.

We use have got to for external obligation like have to. but it is more informal than have to and more common in speech than in writing (have got to is rare in US English):

• What time have we got to be at the airport tomorrow?
• [Claim forms have got to be date-stamped before payment will be made.]

 ✓  Claim forms have to be date-stamped before payment will be made.

We use should/ought to + have + past participle for an unfulfilled obligation in the past:

• You really should have/ought to have registered before term started.
• The record was finally released eighteen months later than it should have been

Necessity

We can use need to, must and have to to express necessity (i.e. a requirement that results from things other than just commands, rules or laws):

• All living beings need to/ must/ have to take in sustenance in order to live.
• I really need to/ must/ have to get some more sleep. I ‘m always exhausted.

Note: It is possible, though quite rare today, to use need without to in questions:

• Need he really play his music so loudly?

If we want to express a necessity without suggesting who should deal with it, we can use need + -ing form:

• That poor bird – his cage really needs cleaning

This use has a passive meaning and is similar to the passive infinitive:

• That poor bird – his cage really needs to be cleaned.

Other Ways of Expressing Obligation

We can use be to for an order from a person in authority:

• The members of the jury are to report to the judge’s chambers.

We use be obliged to (US: obligated to) or required to informal contexts:

• We’re obliged to contribute twenty-five percent of the costs of the repairs.
• Motorists are required by law to wear seat belts in the European Union.

We use be supposed to for a lesser obligation and one that is frequently ignored:

• We’re supposed to leave our textbooks at school, but we often take them home.

We use be liable to for obligation (often in a legal context):

• Anyone causing damage will be liable to pay for all necessary repairs.

Prohibition and Criticism

Forms

Meaning and Use

We use must not (usually mustn’t) to express a prohibition (an obligation not to do something) imposed by the speaker or writer:

• You mustn’t touch that kettle. It’s hot!

To express a weaker, often moral prohibition, we use shouldn’t or oughtn’t to:

• You really shouldn’t/oughtn’t to speak to your mother like that!

We tend to use shouldn’t more often than oughtn’t to.

To express prohibition by an external authority we often use other modal verbs or non- modal expressions. Mustn’t may appear too strong in these situations:

• Guests may not use the pool after 11 p.m. (formal)
• Women can’t/ aren’t allowed to drive in some Arab countries.

Note: It is possible, though not common, to use must not have + past participle for a present prohibition which relates to the past:

• Entrants must be aged 16 to 25 and must not have done any professional modeling. (The modeling is in the past, but the prohibition is in the present.)

We use couldn’t or wasn’t / weren’t allowed to for prohibition in the past:

• We couldn’t go into the disco because we were too young.
• Journalists were shown the disused buildings but they weren’t allowed to enter them.

We use shouldn’t/ ought not to have + past participle to criticize a past action:

• You shouldn’t have driven through that red light. You could have caused an accident.

We usually use won’t be allowed to or can’t to express prohibition in the future:

• Let’s eat before we go. We won’t be allowed to/can’t take food into the auditorium.

Absence of Obligation or Necessity

Forms

Meaning and Use

We usually use don’t have to/ don’t need to to express a lack of external obligation:

 X You mustn’t pay to visit most museums in Britain.

 ✓  You don’t have to pay to visit most museums in Britain. (Entrance is free.)

We use don’t need to/ needn’t for the absence of necessity felt by the speaker. Needn’t tends to express the speaker’s personal opinion more:

• We needn’t/ don’t need to put the heating on yet; it’s not cold enough.

We use didn’t have to/ didn’t need to for absence of obligation in the past:

• You didn’t have to/ didn’t need to finish the washing-up. I could have done it.

Note: Need has two past forms: didn’t need to and needn’t have done. We use didn’t need to when we don’t know if the action happened or not:

• We didn’t need to take warm sweaters, as the weather was so good. (We don’t know if the speaker took warm sweaters or not.)

We use needn’t have + past participle when the action happened but was unnecessary:

• We needn’t have taken warm sweaters. We could have used the space in our luggage for more books! (We know that the speaker took warm sweaters.)

We use won’t have to, won’t need to or needn’t for the absence of obligation in the future:

• With one of the new generation of food processors, cooks won’t have to I won’t need to/needn’t peel or chop anymore.

Recommendation and Advice

Forms

Meaning and Use

We use must for strong recommendations and advice:

• You really must read Sebastian Faulks’s latest book. It’s stunning!
• You must do something about that cough. Please go and see the doctor.

Note that this use must is usually heavily stressed in speech.

Recommendation or advice with should or ought to is less emphatic:

• Even people as young as twenty-five should consider a personal pension.
• Children ought not to spend long periods in front of a computer screen.

We often use should and ought to with the passive:

• The underlying shift in public opinion ought not to be exaggerated.

Had better (not) expresses the best thing to do in a particular situation. It often has a sense of urgency and can be a warning or a threat:

• If the burglars took your keys, you’d better change the locks in case they come back.
• Your dog had better not dig up my rose bush again!

See also:

• IELTS Grammar books
• English Pronunciation in use Intermediate pdf

Logical Deduction and Probability

Forms

In this sense, we can also use must, have to and should with the continuous:

• That disco is so loud. You must be damaging your ears when you go there.
• You have got to be joking! That was not a foul!
• The accused should not have been driving at 80 in a built-up area.

Meaning and Use

We use must for something that we believe to be true because of evidence (i.e. we are making a logical deduction):

• This must be the place – it’s the only restaurant in the street.
• I thought the eclipse was today, but it must be happening tomorrow.

The opposite of must in this sense is can’t, not mustn’t :

• This can’t be the place – there’s no one inside and there are no lights on.

It is possible to use ‘have (got) to’ for emphatic logical deduction:

• There has (got) to be some mistake. I didn’t order this furniture.

We use ‘must-have’ + past participle to express a logical deduction about the past:

• There was a terrific noise last night. It must have been an explosion.
• I couldn’t wake you this morning. You must have been sleeping really soundly.

The negative of this is ‘can’t/couldn’t have’ + past participle.

Note the difference between the two past forms ‘must-have’ + past participle and ‘had to’.

• The Corrs’ new single has been played non-stop. You must have heard it! (deduction)
• I’ve always loved The Corrs and when I heard they had a new single out, I had to hear it! (obligation imposed by the speaker)

We use should/ ought to for probability and shouldn’t /ought not to for improbability. We believe the statement to be true because of our prior knowledge, experience or present evidence:

• The plane should be landing about now.
• There shouldn’t be problems with traffic at that time of the evening.

Note: We rarely use should to ‘predict’ a negative (unpleasant) situation. Instead we use will:

 X  There should be problems with traffic at that time. The roads should be awful.

✓  There’ll be problems with traffic at that time. The roads will be awful.

We use should (not)/ ought (not) to + have + past participle to talk about the probability of an action in the past:

• I don’t know where our main speaker can be. He should have arrived hours ago.

Practice Exercise

Q 1.

Complete the dialogue with the best words or phrases from the box. Use each word or phrase once only.

Beth: Hello. Reception said that you wanted a word with me.

Lisa: That’s right. I’m interested in joining your gym. What (1)___ do?

Beth: Take a seat. First, you (2)____fill in this form. It asks for details about you and    your state of health. We want to be sure that you’re fit enough to use the gym.

Lisa: Okay. I have a slight problem with one knee. I twisted it a few weeks ago.

Beth: Well, you really (3) ____tell the instructor about that, then he’ll make sure that your fitness program takes account of it.

Lisa: Fitness program?

Beth: Yes. If you join, you (4)____have an induction session with one of our fitness instructors. He’ll design a program suited to your level of fitness.

Lisa: Oh, that’s good. Now. it’s £30 a month, isn’t it?

Beth: Well, yes, but that’s the special rate if you take out an annual subscription, so you’re (5)____join for the whole year to get that rate. Otherwise, it’s £40 a month.

Lisa: I see. Yes, I think I’ll join for the year. Is there anything else I should know?

Beth: Let’s see … there are some rules, but they’re pretty obvious. Of course, every one (6)____ wear appropriate clothing and footwear. There are lockers outside the gym, so you’re not (7)____ take anything in with you. but we don’t apply that rule very strictly. You’ll probably want to take a towel and a bottle of water in with you anyway: you (8) ____drink plenty of water while you’re exercising, to prevent dehydration.

Lisa: Yes, are there any restrictions, like (9)____ book time ahead in the evenings?

Beth: No. You can use the gym whenever it’s open. Obviously, if you think a piece of equipment isn’t working properly and (10)____ mending, tell an instructor. Also, for your own good, you (11)____tell us if you feel unsure about how to use a particular machine.

Lisa: Of course. Now, the receptionist said I (12)____provide a photo for the membership card, but I’m afraid I don’t have one on me.

Beth: That’s OK. Bring it next time you come. Until then you can use your receipt as proof of membership.

Q 2.

Read the letter on the next page and decide which word or phrase below fits each space. In each case, only one answer is possible. Circle the letters you choose. The first one is given as an example (0).

Hilverstone Fox Watch

Dear New Member,

Many thanks for your application form for membership of the HFW (Hilverstone Fox Watch). Before I introduce the club to you, I would like to point out that you (0) __pay your subscription until your membership application has been processed and approved, so those of you who joined at the fete last Saturday (1) ___provided cheques on the spot. Our representative (2) ___accepted your cheques. I am returning them where necessary, with apologies for any inconvenience.

HFW was set up three years ago for two reasons: to lobby for the abolition of fox-hunting – the founder members felt we (3)___do this as the Hilverstone Hunt is so powerful in this area – but also to provide some protection for the urban foxes here, who (4) __subsist on household scraps in some cases. Our meetings are fortnightly but please do not feel that you (5) ___attend each one. All our members, however, (6) ___attend six meetings a year and at least two all-night watches. We (7) ___insist upon this to prevent all of the work from falling on the shoulders of a few people.

One or two words of advice: a lot of people interested in foxes attempt to domesticate them by putting food down for them. Please – you (8) ___do this. For one thing, we (9) ___encourage vermin under local by-laws (and foxes are classed as vermin), but also, we (10)___ try to reintroduce these foxes to their natural habitat, as they are not naturally domestic creatures. Please remember also that female foxes with young cubs can be quite aggressive: children in particular (11) ___to go near them at this potentially dangerous time.

Finally, may I remind you that members of HFW (12) ___involved in the Hilverstone Hunt for at least one year prior to joining.

Thank you once again for your interest. I enclose a timetable of our meetings and events for the next three months, and look forward to welcoming you to one of them.

Yours faithfully,

Jonathan Harker

Q 3.

Complete texts A-C with an appropriate verb or expression. Use the information in the box to help you. The first one is given as an example (0).

Requirements of Course

Desk-Top Publishing

• Ten-week intensive course for people interested in producing small-scale publications. Applicants for this course (0) _must_ have good keyboarding skills but are not (1)___ to have prior publishing experience. If possible, applicants (2) ____ have access to a computer and Microsoft Publisher, but there are a limited number of machines available at the college.

Desk-Top Publishing

• Learn how to self-publish from the professionals! We offer Desk-top Publishing courses to suit all schedules and budgets, from five-week intensive courses to year-long evening courses. You (3) ___have your own computer (on our full-time courses) but you (4) ____have some previous experience in publishing. You (5) ____be able to use a keyboard. Call us on 01202 867349

Desk-Top Publishing

• One-year course. Applicants (6) ___have previous experience in publishing, as part of the course involves work experience with a local printing company. Equally, you are not (7) ____to have good computer skills as all basic training is provided. A minimum of three GCSEs is (8) ___and applicants (9) ___have a good level of English.

Q 4.

Write four statements making deductions about each picture. Use the words and phrases underneath the pictures. The first one is given as an example (0).

• (daughter) They must ___be waiting for their daughter___

1. (on/train) She can’t____
2. (miss/it) She must____
3. (child/mother) She must____
4. (phone/parents) She can’t____
5. (rain) It must___
6. (slip/banana skin) The man must____
7. (not/wife) She can’t___
8. (ambulance) Someone must____

Q 5.

For each of the sentences below, write a new sentence as similar in meaning as possible to the original sentence, but using the word(s) given. The word(s) must not be altered in any way.

• It looks certain that the orchestra’s instruments are arriving on a later plane.
• must    ___The orchestra’s instruments must be arriving on a later plan___
• I strongly recommend you to try this sundried tomato bread.

1. must___

• There is no obligation to get an international driving license for this country.

2. have____

• It was stupid of the government to try to break the strike.

3. should____

• I warn you not to chat up with my girlfriend again!

4. had____

• We didn’t book the table but it didn’t matter as there was hardly anyone in the restaurant anyway.

5. need____

• My hair’s much too long. I’ll have to get it cut soon.

6. cutting____           

• It is essential that you disconnect the gas supply before removing the boiler.

7. be disconnected____      

• The management will not permit latecomers to enter the theatre until there is a suitable break.

8. allowed____

• Why do we have to state ethnic origin on official forms these days?

9. required_____     

• There can be no doubt that the solicitor has received the information by now.

10. must_____

• It probably won’t be difficult to get tickets for the first night.

11. should_____

• It is essential that patients have not eaten or drunk anything for three hours before the operation.

12. must_____

Q 6.

Underline six more mistakes to do with modal verbs or expressions from this unit, then correct them.

Minutes of Holmefield Neighbour Care meeting

1. Sergeant Dibden reminded us that we don’t have to tackle a burglar if one ==> mustn’t
2. enters our home as this can be very dangerous. He also reminded us that we
3. are supposed by law to inform the police and our insurance companies of all
4. keyholders after a break-in.
5. Mrs. Sanders from Twyfield Close reported that she had been burgled two
6. afternoons before. The burglar should have got in through an open downstairs
7. window, although at that time of day there must be plenty of people
8. around who witnessed the break-in. You’d better report it to the police if you
9. saw anything as it’s our civic duty.
10. Mr. Harrison from Dukes Avenue was concerned that he hadn’t taken up an
11. invitation from a security company to assess his house for security risks, but he
12. was relieved to discover from Sergeant Dibden that he needn’t have invited
13. them anyway, as the police can do security checks.
14. Finally, remember, if you need to speak to a police officer, you can call Sergeant
15. Dibden at Holmefield police station at any time.

Answer Key for Diagnostic Test

1. Having to
2. ought to
3. have to
4. have to
5. shouldn’t have
6. need
7. are supposed to
8. couldn’t go
9. are not allowed to
10. must not have
11. needn’t
12. don’t have to
13. didn’t need to show
14. better
15. should
16. had better not
17. be raining
18. shouldn’t
19. must have
20. had to have

Answer Key for Practice Test

Q 1.

1. do I have to
2. have to
3. must
4. will have to
5. obliged to
6. has to
7. supposed to
8. should
9. having to
10. needs
11. need to
12. had to

Q 2.

1. A
2. B
3. C
4. B
5. C
6. A
7. C
8. C
9. A
10. B
11. A
12. B

Q 3.

1. required
2. should
3. need not/do not have to
4. must
5. should
6. need not/do not have to
7. required/obliged
8. required/necessary
9. should

Q 4.

1. She can’t have been on the train.
2. She must have missed it.
3. She must be the child’s mother.
4. She can’t have phoned her parents.
5. It must have been raining.
6. The man must have slipped on the banana skin.
7. She can’t be his wife.
8. Someone must have phoned for an ambulance.

Q 5.

1. You must try this sundried tomato bread.
2. You don’t have to get an_
3. The government should not have tried to_
4. You had better not chat up_
5. We didn’t need to book the table as_
6. My hair’s much too long. It needs cutting soon.
7. The gas supply must be disconnected before you remove the boiler/before the boiler is removed.
8. Latecomers will not be allowed to enter the theatre
9. Why are we required to state
10. The solicitor must have received
11. It should not be difficult
12. Patients must not have eaten or drunk anything

Q 6.

Line 3: supposed ==> obliged/required

Line 6: should have got in ==> must have got in

Line 7: there-must be ==> there must have been

Line 8: You’d better report it ==> You should/ought to report it

Line 12: needn’t have invited ==> didn’t need to invite

Line 14: need ==> need to