Forms 6a,6c1,6c2. Comparisons

https://www.ego4u.com/en/cram-up/grammar/adjectives-adverbs/adjectives/compare-exercises?3;

http://www.englishexercises.org/makeagame/viewgame.asp?id=6009;

http://www.englishexercises.org/makeagame/viewgame.asp?id=2070;

https://www.english-4u.de/en/exercises/comparison.htm.