cook lunch (obligation)
He must / He has to cook lunch.
work (no obligation)
He doesn't have to / He needn't work.
dance (obligation)
She must / She has to dance.
use a computer (no obligation)
He doesn't have to use a computer.
smoke
You mustn't / You can't smoke here.
paddle (obligation/necessity)
They have to / They need to / They must paddle.
take your dog
You mustn't / You can't take your dog there.
try it on (obligation)
You must / You have to try it on.
play the guitar (no obligation)
He needn't / He doesn't have to play the quitar.
make noise? (obligation)
Must they / Do they have to make noise?
drink water? (obligation)
Do they have to drink water?
drive carefully
You have to / You must drive carefully.
ride a bike (no obligation)
He doesn't have to / He needn't ride a bike.
play football (no obligation)
He doesn't have to / He needn't play football.
swim alone (negative obligation)
Children mustn't swim alone.
go home (obligation)
We have to go home now / at (time).
