Modal verbs - OBLIGATION

Modal verbs - OBLIGATION

1. MUST

   • strong obligation of the speaker / writer
     • Students must pass the test to obtain a certificate.
   • suggestion, advice or recommendation the speaker or writer feels
     • You must watch Game of Thrones.

2. HAVE TO / HAS TO

   • strong obligation of a third person
     • You have to get a visa if you want to visit the US.

3. MUSTN'T

   • Prohibition
     • I mustn't smoke in class.

4. DON'T HAVE TO / DOESN'T HAVE TO

   • NO obligation / necessity
     • I don't have to wear formal clothes on Fridays.

5. PAST - two situations:

   • I DIDN'T HAVE TO GO to school last Monday (not necessary, so not done)
     • I NEEDN'T HAVE GONE to schools last Monday (not necessary, but I did it anyway)

6. DON'T NEED TO / DOESN'T NEED TO / NEEDN'T

   • NO necessity
     • I needn't buy any milk today.

7. NEED TO

   • Needs or necessities
     • I need to revise for the exam.