[Modal auxiliaries] Expressing Necessity: Must, Have To, Have Got to

	degree
I must study.	Very important
I have to (need to ) study. have to (hafta) has to (hasta)	Important
I have got to(gotta) study.	Not so important

You need not do this!

Visa is a must.

black book

(c) 7. If you dog is running free and the police stop you, you will probably ___ pay a fine.

a. must

b.must not

c have to

d. don't have to (must 用未來式怪怪的)

You have to finish your project before getting off work.