need must may 提问时，肯定和否定分别怎么回答？

need /needn't
must /mustn't
may /may not

must yes, you must./you have to
no, you needn't 千万别用mustn't
need yes, you must.
no, you needn't
may yes, you may
no, you may not

Must I finish doing my homework?
Yes,you must.
No,you needn't.
May I use your pen?
Yes,you can.
No,you can't.

must-Yes,you should./No,you needn't.
need-Yes,you should/may/can/need./No.you needn't/musn't.
may-Yes,you may/can./No,you musn't/can't.