Using must

Using must

Must is used to express several different ideas.

To express compulsion

  • You must do your homework before going to bed.
  • You must finish this work before Monday.
  • You must attend the conference.

To express duty

  • We must serve our country.
  • We must love our brethren.

To express obligation

  • We must respect our elders.
  • We must obey our parents and teachers.

To express necessity

  • We must get the roof repaired before monsoon sets in.
  • You must get a good job.

To give advice

  • You must change your clothes before leaving for office.
  • You must stop smoking.
  • You must exercise regularly.
  • You must avoid fatty foods.

To express some possibility or expectation

  • She must be back in a short while.
  • That must be interesting.
  • He must be working.

To express a logical conclusion

  • She must be nearly 40.
  • He must be joking.
  • She must be a miserable house wife.

Must refers to the present or future. In the past tense, we use had to to express similar ideas.

  • I had to do the paint job again.
  • I had to wait for them for two hours.

Instead of must, we can use will have to to talk about future obligation.

  • You will have to reach the station by 6.30. (OR You must reach the station by 6.30.)

The structure must have + past participle can refer to the past.

  • She must have reached home by now.
  • It must have been past mid-night when Dad returned home.

Must not

Must not is used to prohibit.

  • You must not tease the dog.
  • You must not smoke.
  • You must not be late for office.
  • You must not waste your money.