Four kinds of obligation English keeps apart

Examples

1. Visitors are to report to reception on arrival.

2. You do not have to come, but I would like you to.

3. We were supposed to hear by Friday and nobody rang.

4. You had better keep the receipt.

Common mistakes

• ✗Wrong: You must not come if you are busy.

  ✓Right: You do not have to come if you are busy.

  must not forbids; the absence of obligation is do not have to.

• ✗Wrong: I needn’t have worried, so I did not worry.

  ✓Right: I needn’t have worried, but I did.

  need not have means you DID it and it turned out to be unnecessary.

• ✗Wrong: You had better to lock it.

  ✓Right: You had better lock it.

  had better takes the bare infinitive.

Practice questions

Try each one yourself first, then open “Show answer” for the solution and the reason.

1. 1Choose the correct sentence.

   1. AYou have not to bring anything.
   2. BYou do not must bring anything.
   3. CYou do not have to bring anything.
   4. DYou must not bring anything.
   Show answer

   Answer: C You do not have to bring anything.

   No obligation, not a prohibition.

2. 2Choose the correct sentence.

   1. ACandidates are to leaving their phones outside.
   2. BCandidates are to leave their phones outside.
   3. CCandidates to leave their phones outside.
   4. DCandidates are leaving their phones outside.
   Show answer

   Answer: B Candidates are to leave their phones outside.

   be to gives an official instruction.

3. 3Choose the correct sentence.

   1. AShe was supposed ring on Monday.
   2. BShe supposed to ring on Monday.
   3. CShe was supposed to ring on Monday.
   4. DShe is supposed rang on Monday.
   Show answer

   Answer: C She was supposed to ring on Monday.

   be supposed to keeps the to.

4. 4Fill in the gap.

   Guests _____ smoke anywhere in the building.

   1. Ahad better not to
   2. Bneed not
   3. Cdo not have to
   4. Dmust not
   Show answer

   Answer: D Guests must not smoke anywhere in the building.

   A prohibition takes must not.

5. 5Fill in the gap.

   We _____ pay for the survey; the seller had already done it.

   1. Aneed not have
   2. Bhad not to
   3. Cmust not
   4. Ddid not need to
   Show answer

   Answer: D We did not need to pay for the survey; the seller had already done it.

   The action was not required and was not done.

6. 6Fill in the gap.

   I _____ brought an umbrella; it never rained.

   1. Adid not need to
   2. Bmust not have
   3. Cneed not have
   4. Dshould not
   Show answer

   Answer: C I need not have brought an umbrella; it never rained.

   It WAS done and turned out unnecessary.

7. 7Fill in the gap.

   You _____ get there early if you want a seat.

   1. Ahad better to
   2. Bwould better
   3. Chad better
   4. Dbetter had
   Show answer

   Answer: C You had better get there early if you want a seat.

   had better plus bare infinitive.

8. 8Fill in the gap.

   Under the contract the tenant _____ keep the garden tidy.

   1. Ais requiring
   2. Bis required
   3. Cis required to
   4. Drequires to
   Show answer

   Answer: C Under the contract the tenant is required to keep the garden tidy.

   A written obligation in the passive.

9. 9This sentence is wrong. Choose the fix.

   Which sentence is wrong?

   1. AYou must not to park here.
   2. BParking here is prohibited.
   3. CYou must not park here.
   4. DYou are not allowed to park here.
   Show answer

   Answer: A You must not to park here.

   Modals never take to.

10. 10This sentence is wrong. Choose the fix.

    Which sentence is wrong?

    1. AWe need not sign it today.
    2. BIt is not necessary to sign it today.
    3. CWe do not have to sign it today.
    4. DWe do not must sign it today.
    Show answer

    Answer: D We do not must sign it today.

    must has no do form.