To indicate simple futurity or probability:
Use shall with I and we; use will with all other subjects.
To indicate promise, determination, threat, or command on the part of the speaker; i. e., action which the speaker means to control;
Use will with I and we; use shall with all other subjects.
Examine the following examples of the correct use of shall and will:
Statements as to probable future events:
We shall probably be there.
I think you will want to be there.
It will rain before night.
Statements of determination on the part of the speaker:
I will come in spite of his command.
You shall go home.
It shall not happen again, I promise you.
66. Shall and Will in Questions. In interrogative sentences shall should always be used with the first person. In the second and third persons that auxiliary should be used which is logically expected in the answer.