Shall or will?
The traditional rule is that shall is used with first person pronouns (i.e., I and we) to form the future tense, while will is used with second and third person forms (i.e., you, he, she, it, they). For example:
I shall be late
They will not have enough food.
However, when it comes to expressing a strong determination to do something, the roles are reversed: will is used with the first person, and shall with the second and third. For example:
I will not tolerate such behavior.
You shall go to the ball!
In practice, though, these distinctions have faded, and the word shall is now seldom used in any normal context in American English.