Modals of Possibility

I'm sure it is true " I'm not sure " I'm sure it isn't true

MUST - COULD - MAY - MIGHT - CAN'T/COULDN'T

Could, may, might	Possibility for the future	I may be late for class
Could, may, might	Uncertainty	He could be lost
May not, might not	Uncertainty	They might not like it
Must, Can’t	Certainty	She can’t be married