Forms 6a,6c. Preparation for the test

https://www.englisch-hilfen.de/en/exercises/tenses/be.htm;
https://www.englisch-hilfen.de/en/exercises/tenses/be2.htm;
https://www.englisch-hilfen.de/en/exercises/tenses/have_to.htm;
https://www.ecenglish.com/learnenglish/lessons/have-or-has;
https://www.englisch-hilfen.de/en/exercises/various/there_is_there_are.htm;
https://www.englisch-hilfen.de/en/exercises/various/there_is_there_are2.htm;
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=lt&selLanguage=en;
http://www.englishexercises.org/makeagame/viewgame.asp?id=723.