SAYING WE ARE SURE SOMETHING WILL HAPPEN

We can use will and shall to talk about what will happen.

Exports will continue to rise over the next few months.
I shall be staying in Tokyo for the next three days.
We shan't stay long: we have to be at Mary’s by six.

Asking for permission

 We use  can, could, may and  might to ask for permission, depending on the situation.

1.  Can is the commonest and most informal: Can I borrow your umbrella (please)?
2.  Could is more polite than can: Could I borrow your umbrella (please)?
3.  May is more formal, more respectful than can and could: May I borrow your umbrella (please)?
4.  Might is the most polite but the least common: Might I borrow your umbrella (please)?
5.  We can add possibly and use the expressions like Do you think and  I wonder if to make requests even more polite.

We use can to say that someone has the ability or opportunity to do something. The negative of can is cannot (contraction: can't).