U13 - Present Simple vs. Continuous
https://www.ego4u.com/en/cram-up/grammar/simpre-prepro/exercises?ex08
http://anglictina.chrustova.eu/cviceni/present-simple-vs-continuous.php
https://www.englisch-hilfen.de/en/exercises/tenses/simple_present_progressive2.htm
https://elt.oup.com/student/solutions/preint/grammar/grammar_01_012e?cc=cz&selLanguage=cs