Your taskFill in the gap in each sentence with the correct word or phrase.mustmustn'tdon't have tohave tomustn'tdon't have tomustdoesn't have tomustn'thave todon't have tomustn'thas tomustn'tdon't have to0 / 15 answeredYour score0 / 150%Keep practising! Focus on the explanations below.1You wear a seatbelt in a car — it's the law.Correct answer: must▸ Why?"Must" or "have to" both express strong obligation. The law makes this an external rule, so "have to" is equally correct.2You use your phone while driving — it's illegal and very dangerous.Correct answer: mustn't▸ Why?"Mustn't" = it is forbidden. "Don't have to" would mean it is not necessary, which is completely wrong — using a phone while driving is prohibited.3It's Saturday — you get up early if you don't want to.Correct answer: don't have to▸ Why?"Don't have to" means it is not necessary (you are free to sleep in). "Mustn't" would wrongly prohibit getting up early.4All students wear a uniform at this school.Correct answer: have to▸ Why?"Have to" expresses an external rule set by the school. "Must" is also acceptable but "have to" better signals an imposed rule.5Children touch the hot oven — they could burn themselves.Correct answer: mustn't▸ Why?"Mustn't" prohibits the dangerous action. "Don't have to" would mean the children are simply not required to touch it, which understates the danger.6The entrance to the museum is free — visitors pay.Correct answer: don't have to▸ Why?"Don't have to pay" = no payment is required (there is no fee). "Mustn't pay" would mean payment is actually forbidden, which is nonsensical here.7You try this café — their coffee is absolutely amazing!Correct answer: must▸ Why?"Must" expresses a strong personal recommendation (almost an obligation to enjoy something). "Have to" also works here in informal speech.8She come to the meeting — she can send her notes by email.Correct answer: doesn't have to▸ Why?"Doesn't have to come" = her attendance is optional. "Mustn't come" would forbid her attendance, changing the meaning entirely.9This is a surprise party — you tell Maria about it!Correct answer: mustn't▸ Why?"Mustn't tell" = it is forbidden to tell her. "Don't have to tell" would mean telling is merely optional — but the speaker clearly wants it kept secret.10I take the bus to work because my car is broken.Correct answer: have to▸ Why?"Have to take" shows the bus is obligatory due to circumstances. "Must take" is also correct but implies a stronger internal compulsion.11The second essay is optional — you write it if you don't have time.Correct answer: don't have to▸ Why?"Don't have to write" signals freedom of choice. Confusing this with "mustn't write" is the key A2 error — they are opposites in meaning.12You eat food that has passed its expiry date.Correct answer: mustn't▸ Why?"Mustn't eat" prohibits the action for safety. "Don't have to eat" would mean eating it is merely optional — but the safety warning is much stronger.13He finish the report before 5 pm or his boss will be angry.Correct answer: has to▸ Why?"Has to finish" is the correct third-person singular form of "have to". "Must" is also fine here and doesn't change form.14Passengers carry liquids of more than 100 ml through airport security.Correct answer: mustn't▸ Why?"Mustn't carry" states the airport security prohibition. "Don't have to carry" would just mean passengers are not required to carry liquids — missing the prohibition entirely.15You book in advance for the restaurant — they always have tables available.Correct answer: don't have to▸ Why?"Don't have to book" = booking is not required (there's always space). "Mustn't book" would absurdly forbid making a reservation.Check AnswersPlease answer at least one question first.Found an error in this exercise? Let us know.