Modals to express offers: CAN, COULD, WILL, SHALL, MAY
Can, could, will, shall and may are used to express offers:
Can
I
help
you?
May
I
carry
your suitcase, Madam?
(only in first-person questions)
I
could give
you a lift.
Shall
I
copy
this document for you?
(only in first-person questions)
I
will make
you a coffee.