http://www.englisch-hilfen.de/en/exercises/nouns_articles/article_the.htm
https://www.learn4good.com/languages/evrd_grammar/article_ex.htm
https://www.ego4u.com/en/cram-up/grammar/pronouns/exercises?02
https://www.ego4u.com/en/cram-up/grammar/pronouns/exercises?03
https://www.ego4u.com/en/cram-up/grammar/pronouns/exercises