ABVERBS OF FREQUENCY (UNIT 7)

Explanation here.

Exercises here:
https://www.englisch-hilfen.de/en/exercises/adjectives_adverbs/adverbs_of_frequency.htm
https://elt.oup.com/student/solutions/elementary/grammar/grammar_02_012e?cc=global&selLanguage=en
http://www.myenglishpages.com/site_php_files/grammar-exercise-adverbs-frequency.php