1. NECESSITY AND OBLIGATION

2. Expression used in asking necessity and obligation
We must be there before the boss come.
It is necessary for us to be there on time
We must come into the class before the teacher comes
It is necessary for you to tell the truth.

3. Asking necessity and obligation
Acceptig necessary and obligation
Refusing necessary and obligation
Is there anything you need?
Is it necessary to finish it now?
Do you need something?
Must we be nice to Mr. Frendy?
It is necessary for you to be here on time.
You must be here before the boss comes.
You have to submit the report by June 2nd.
Don’t bother with it.
There’s not obligation to continue if you don’t want it.
No need to worry about it.
You needn’t tell the whole truth.