Lesson 26 mustn’t / don’t have to

Choose the correct answers:

  1. People under twenty-one years old __________ (mustn’t, don’t have to, didn’t have to) drink alcohol, but they can drink juice
  2. People at and over twenty-one years old __________ (mustn’t, don’t have to, didn’t have to) drink alcohol. They can choose juice.
  3. At twenty-one, I am allowed to drink alcohol, but I __________ (mustn’t, don’t have to, didn’t have to) drink too much because I will need to drive afterwards.

Explain:

Even though “must” and “have/has to” have similar meanings in the positive forms, they are very different in negative sentences.

mustn’t:   not allowed. It shows clear prohibition, no choice.

don’t/doesn’t/didn’t have to:   no need, not necessary. It implies a choice.

  • In Sentence #1 and #3, there is no choice because of the law.
  • In Sentence #2, people can choose to drink alcohol or not to drink it. It is not necessary to drink alcohol if they do not want to.

 

Review:

  1. An elementary school pupil __________ (mustn’t, doesn’t have to, didn’t have to) stay home alone on a school holiday.
  2. A high school student __________ (mustn’t, doesn’t have to, didn’t have to) stay home alone  on a school holiday. He or she may choose to relax at home or visit friends.
  3. As a college student, my schedule is flexible.  For example, I__________ (mustn’t, don’t have to, didn’t have to) get up early last Monday because my classes are on Tuesdays and Thursdays.

 

 

Answers:

mustn’t; don’t have to; mustn’t

mustn’t; doesn’t have to; didn’t have to

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