How to express possibility using MAY, MIGHT and COULD.
Past
Tinytech Ward may / might / could have learned about Galaxy Tech’s new laptop models when Galaxy Tech’s email servers were hacked.
Present
The engineers of Tinytech Ward may / might / could be studying GT’s plans for the new laptops right this minute!
Future
If TW releases an identical laptop model down the road, GT may / might / could sue TW.
MAY: to say that something is probably going to happen, we use may.
MIGHT / COULD: to say that something may be possible (but we’re not sure), we use might or could.
COULD NOT POSSIBLY: if we believe something is impossible, we use could not possibly.