http://www.grammar.cl/Games/Comparatives_Superlatives.htm
http://www.eslgamesplus.com/action-verbs-present-tenses-esl-interactive-grammar-vocabulary-game/
http://www.englishexercises.org/makeagame/viewgame.asp?id=6009
http://www.learnenglishfeelgood.com/english-comparative-superlative1.html
http://www.eslgamesplus.com/action-verbs-esl-interactive-grammar-vocabulary-game-present-tense/
http://www.verbs-online.com/english-verbs/english-verbs.htm
http://www.agendaweb.org/grammar/comparative-superlative-exercises.html
http://www.ejerciciosinglesonline.com/new-exercises/ex-comparative-superlative/
https://www.gamestolearnenglish.com/compare/