INDEX:
1. when a situation forces you to do something
2. when a rule or law forces you to do something
3. when you feel that you should do something because it would be right
4. when a job, plan etc includes something that you must do
5. when you do not have to do something
6. when you must not do something
RELATED WORDS
see also
↑ FORCE SB TO DO STH
↑ SHOULD/OUGHT TO
↑ INSIST
↑ FORBID
◆◆◆
1. when a situation forces you to do something
▷ must do something/have to do something /ˌmʌst ˈduː something, ˌhæv tə ˈduː something/ [verb phrase]
▪ We must get this work finished today.
▪ Must you leave so soon?
▪ Before we go and see Ian there’s something I have to do.
▪ Do we have to stay for the whole show?
have got to do something
▪ I’ve got to go to London tomorrow for a meeting.
must/have to
▪ I didn’t really want to go by train, but I had to because my car was still being repaired.
▪ I hate to make the trip this time of year, but I really must.
▷ need to do something /ˌniːd tə ˈduː something/ [verb phrase not in progressive]
to have to do something because you think it is necessary or someone else thinks it is necessary :
▪ We need to buy some more potatoes.
▪ Simon knew that he needed to raise the money quickly.
▪ Do I really need to go to this meeting?
▷ be forced to do something /be compelled to do something/be obliged to do something /biː ˌfɔːʳst tə ˈduː something, biː kəmˌpeld tə ˈduː something, biː əˌblaɪdʒd tə ˈduː something/ [verb phrase]
to have to do something that you do not want to do because you are in a situation that makes it impossible to avoid :
▪ She was forced to retire early due to ill health.
▪ We may be obliged to scrap the project if we don’t get more funding.
▪ Organizers were compelled to cancel the event after the sponsors pulled out.
▷ have no alternative /hæv ˌnəʊ ɔːlˈtɜːʳnətɪv/ [verb phrase not in progressive]
to have to do something, even though you do not want to, because there is nothing else you can possibly do in the situation :
▪ The authorities say that they had to close the hospital - they had no alternative.
have no alternative but to do something
▪ He had no alternative but to resign.
2. when a rule or law forces you to do something
▷ must do something/have to do something /ˌmʌst ˈduː something, ˌhæv tə ˈduː something/ [verb phrase]
▪ All competitors must arrive by 10:00 a.m.
▪ All visitors have to sign in at the main reception desk.
▪ I’m not sure what the procedure is -- you might have to make a written complaint.
must/have to
▪ I don’t want to get rid of the animals, but we have to.
▷ be obliged to do something /biː əˌblaɪdʒd tə ˈduː something/ [verb phrase] formal
to have to do something, because of a legal or professional rule :
▪ Doctors are obliged by law to try to keep their patients alive.
▪ Members of parliament are obliged to declare all their financial interests.
▷ be required to do something /biː rɪˌkwaɪəʳd tə ˈduː something/ [verb phrase] formal
to have to do something - used especially in written notices and official documents :
▪ Visitors are required to register their names on arrival.
▪ Under the law the President is required to notify Congress when US troops are likely to be involved in hostilities.
▪ Companies are legally required to keep records of all their financial transactions.
▷ have an obligation to do something/be under an obligation to do something /hæv ən ɒblɪˌgeɪʃ ə n tə ˈduː something, biː ʌndər ən ɒblɪˌgeɪʃ ə n tə ˈduː- something ǁ-ɑːb-/ [verb phrase]
to have to do something because it is the duty of someone in your position to do it, or because you have officially agreed to do it :
▪ Anyone who rents a house is under an obligation to keep it clean and tidy.
▪ Having promised to cut taxes, the government now has an obligation to do so.
▷ compulsory /kəmˈpʌls ə ri/ [adjective]
something that is compulsory must be done, used, or provided because of a rule or law :
▪ Smoke detectors are compulsory in all new buildings.
▪ Compulsory education when all children have to go to school was introduced in 1870.
compulsory for
▪ Maths and English are compulsory for all students.
it is compulsory (for somebody) to do something
▪ It is now compulsory for anyone claiming state benefit to register with a job centre.
▷ mandatory /ˈmændət ə riǁ-tɔːri/ [adjective]
something that is mandatory must be done because of the law :
▪ Drug smuggling carries a mandatory death sentence.
mandatory for
▪ In some countries, wearing helmets is mandatory for all cyclists.
▷ obligatory /əˈblɪgət ə riǁ-tɔːri/ [adjective]
something that is obligatory must be done because of a rule or law, or because it is expected that you will do it :
▪ Evening dress is usual, but not obligatory.
obligatory for
▪ Military service is obligatory for all men between 18 and 27.
it is obligatory (for somebody) to do something
▪ It is now obligatory for all competitors to wear face protectors.
3. when you feel that you should do something because it would be right
▷ must do something/have to do something /ˌmʌst ˈduː something, ˌhæv tə ˈduː something/ [verb phrase]
▪ Everyone will be expecting me so I have to go.
▪ I must write and thank her for the lovely flowers she sent me.
must/have to
▪ I don’t really want to spend Christmas with my family, but I suppose I have to.
▷ feel obliged to do something /fiːl əˌblaɪdʒd tə ˈduː something/ [verb phrase]
to feel that you should do something because other people expect you to do it and will be disappointed or upset if you do not :
▪ I felt obliged to invite all my family, although I didn’t really want to.
▷ feel compelled to do something /fiːl kəmˌpeld tə ˈduː something/ [verb phrase] formal
to feel very strongly that you must do something, because it is the right thing to do and people expect you to do it :
▪ No one should feel compelled to take part. It should be voluntary.
▪ I felt compelled to say something in Henry’s defence.
▷ feel impelled to do something /fiːl ɪmˌpeld tə ˈduː something/ [verb phrase] formal
to feel that it is your moral duty to do something :
▪ I feel impelled to write and tell you how disappointed I am with your newspaper.
▪ Sarah felt impelled to stay at home and look after her parents.
4. when a job, plan etc includes something that you must do
▷ entail /ɪnˈteɪl/ [transitive verb not in progressive]
if a job, plan, piece of work etc entails something, you have to do it because this is part of the job, plan etc :
▪ I didn’t want to take on a job that would entail a lot of travelling.
entail doing something
▪ The job entailed being on call twenty-four hours a day.
▷ involve /ɪnˈvɒlvǁɪnˈvɑːlv/ [transitive verb not in progressive]
if something such as a job, plan, decision etc involves something, you have to do it because it is part of the job, plan etc :
▪ Community service can involve anything from gardening to helping in old people’s homes.
involve doing something
▪ The plan involves converting the old canteen into a sports hall.
5. when you do not have to do something
▷ not have to do something /nɒt ˌhæv tə ˈduː something/ [verb phrase not in progressive]
if you do not have to do something, you can do it if you want, but you are not forced to do it, either by a rule or by another person, or by the situation you are in :
▪ Paola was fortunate in that she came from a wealthy family and didn’t have to work.
▪ You don’t have to go if you don’t want to.
▷ there is no need to do something /ðeər ɪz ˌnəʊ niːd tə ˈduː something/ spoken
say this to tell someone that it is not necessary for them to do something :
▪ There’s no need to do the dishes - I’ll do them in the morning.
there’s no need for somebody to do something
▪ There’s no need for you to bring any food - it’s all being provided.
▷ unnecessary/not necessary /ʌnˈnesəs ə riǁ-seri, nɒt ˈnesəs ə riǁ-seri/ [adjective]
if something is unnecessary or not necessary, it is not needed or there is no good reason for you to do it :
▪ They want to build another shopping mall here, but we think it’s completely unnecessary.
it is unnecessary/not necessary to do something
▪ It’s not necessary to wash your hair every day.
▷ not need to do something/needn’t do something /nɒt ˌniːd tə ˈduː something, ˌniːdnt ˈduː something/ [verb phrase not in progressive]
to not have to do something, because it is not necessary :
▪ You don’t need to tell Sandy - she already knows.
▪ You needn’t come with me - I can find my own way to the station.
▪ Marian was one of those lucky students who didn’t need to work hard to do well.
▷ be under no obligation to do something /biː ʌndəʳ nəʊ ɒblɪˌgeɪʃ ə n tə ˈduː something ǁ-ɑːb-/ [verb phrase]
to not have to do something if you do not want to, especially in a situation where you might feel that you have to because other people will be upset or disappointed if you do not :
▪ The firm is under no obligation to offer you a job.
not be under any obligation to do something
▪ You are not under any obligation to buy anything.
▷ optional /ˈɒpʃ ə nəlǁˈɑːp-/ [adjective]
if something is optional, you do not have to do it or use it but you can if you want to :
▪ You don’t have to do French - it’s optional.
▪ The holiday price includes entertainment in the evenings, and there are optional excursions on offer every day.
optional for
▪ General Studies is optional for sixth-form students.
▷ voluntary /ˈvɒlənt ə riǁˈvɑːlənteri/ [adjective]
a voluntary activity is one that you do because you want to do it, especially because you believe it is useful or will help other people, and not because you have to :
▪ The council is trying to get more young people involved in doing voluntary work.
▪ We get all our money from voluntary contributions.
6. when you must not do something
▷ must not/mustn’t /ˈmʌst nɒt, ˈmʌs ə nt/ [verb]
use this to tell or order someone not to do something :
▪ This book must not be removed from the library.
must not/mustn’t do something
▪ Remember, you mustn’t tell anyone about this.
▷ can’t /kɑːntǁkænt/ [verb] spoken
use this to say that someone is not allowed to do something :
▪ ‘Ben wants to borrow the car.’ ‘Well tell him he can’t.’
can’t do something
▪ I’m sorry, you know I can’t discuss my work - it’s confidential.