For practicing:
https://agendaweb.org/exercises/verbs/used-to/affirmative-negative-questions-1.htm;
https://www.usingenglish.com/quizzes/326.html;
https://test-english.com/grammar-points/b1-b2/used-to/;
https://test-english.com/grammar-points/b1-b2/used-to/2/;
https://test-english.com/grammar-points/b1-b2/used-to/3/;
https://www.engblocks.com/grammar/exercises/used-to/used-to-get-used-to-be-used-to/.