You can train on the passive with those exercises and your photocopies and copybooks.
https://learnenglish.britishcouncil.org/en/english-grammar/verbs/active-and-passive-voice
https://www.ego4u.com/en/cram-up/tests/hadrians-wall
http://www.perfect-english-grammar.com/passive-exercise-1.html
http://www.perfect-english-grammar.com/passive-exercise-2.html
http://www.perfect-english-grammar.com/passive-exercise-3.html
http://www.perfect-english-grammar.com/passive-exercise-4.html
http://www.perfect-english-grammar.com/passive-exercise-5.html
http://www.perfect-english-grammar.com/passive-subordinate-clauses-exercise-1.html