could, may, might如何運用？

MAY 你想這些東西會發生但你不肯定 i may finish the jigsaw puzzle
↓ today.There are fifty pieces left.
MIGHT
↓
COULD 這些東西可能會發生但可能性低
i could finish the jigsaw puzzle .There are one thousand pieces left.



希望可以幫到你啦！