Shall

http://www.merriam-webster.com/dictionary/shall

In this link we can see diferent uses for the modal verb Shall, which is very used in british english but not so commom in american english.
Althought its form is not so common it is still very important to use this modal verb specificly to be more polite, just like british people like it.
It is a very important and archaic verb.
Lets discuss and then try to understand its forms and uses.
Negatives and interrogatives are also really important to be used with this form.
Enjoy!