Modals

can

could

may

should

might

will

must

would

Examples:

I attend class.	General declaration of fact. Attending class is something I normally do.
I can attend class.	Expresses ability. I have the means (time and transportation) to attend.
I might attend class.	Expresses possibility, but not certainty. Maybe I will attend; maybe I won't.
I will attend class.	Expresses future intent. I resolve to do it at some later time.
I should attend class .	Expresses mild obligation. It is required, and I expect to comply.
I could attend class.	Expresses possibility. If I have nothing else to do, I might attend.
I would attend class.	(In this case), expresses reservation. If I had the time (but I don't)…
I must attend class.	Expresses strong obligation. I am required and have to comply.