ELLLO Low Intermediate English Lesson #4-08

Modals of Obligation

Watch these videos to learn how to use modal to talk about responsibilites.

Grammar Point

Point 1: We use the modals must, need to, and have to for actions that are obligations.
  1. You must hurry.
  2. You need to finish this.
  3. I have to go now.
  4. We need to pay the bill.
Point 2: All the modals are very similar in meaning but must is stronger than have to or need to.
  1. You must take your medicine. (strong)
  2. You have to take your medicine. (not as strong)
  3. You need to take your medicine.
Point 3: The negative forms have very different meanings. Must not or mustn't is a command to not do something.
  1. You mustn't go there. / You can't go there.
  2. She mustn't trust him. / She can't trust him.
  3. They mustn't be late. / You can't be late.
  4. You mustn't lose this. / You can't lose this.
Point 4: When we say you don't need to, or don't have to do something, then it is an option or not necessary.
  1. You don't have to wear a tie. / It is OK not to wear a tie.
  2. You don't need to be there. / It is OK not to go.
  3. She doesn't have to pay me back. / She can keep her money.
  4. He doesn't need to ask her. / It is OK to not see her.

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