USED TO / WOULD

https://learnenglish.britishcouncil.org/en/quick-grammar/past-habit-used-towouldpast-simple

https://elt.oup.com/student/solutions/upperint/grammar/grammar_02_012e?cc=mx&selLanguage=en

http://www.esl-lounge.com/student/grammar/3g11-used-to-would.php

http://www.tolearnenglish.com/exercises/exercise-english-2/exercise-english-26509.php