Put the verb in brackets into the future simple. For example,(join, +) Go now, I'll join you later.(open, -) I can't get in, the door won't open.
(let, -) We you down, you can rely on us.
will (= 'll)
will not (= won't)
We can also say "I shall" or "we shall". It is the same as "will". Note that we do not use "shall" with other persons: you/he/she/it/they will.