can i ...
---yes,you can
---no,you can't
may i...
----yes,you may
----no,you mustn't/can't
must i...
----yes,you must.
----no,you needn't/no,you don't have to
can i ...
---yes,you can
---no,you can't
may i...
----yes,you may
----no,you mustn't/can't
must i...
----yes,you must.
----no,you needn't/no,you don't have to