In this unit we are going to learn the verbs COULD / COULDN'T. They are in the past form, and their present is CAN / CAN'T.
Let's practise! Click on the image to do some exercises.
More practise:
http://www.perfect-english-grammar.com/support-files/modals_of_ability_1.pdf
https://www.tolearnenglish.com/exercises/exercise-english-2/exercise-english-91443.php
*http://learnenglishkids.britishcouncil.org/en/grammar-practice/modals-could-and-couldnt
*: click on Game to play!