If you want someone to do something, you ask if they _____ do it for you.

If you have strong evidence that something good will happen in the future you say it _____ happen.

If you think it's possible that something will happen in the future you say it _____ or _____ happen.

If you want to give someone strong advice you say they ____ do something.

If you want to make a suggestion you say someone _____ do something.

If you're talking about an ability in the past you say that someone _____ do something.

If you're talking about a habit in the past you say someone _____ do something.