Comparatives and superlatives:
https://www.myenglishpages.com/english/grammar-exercise-grammar-comparatives-superlatives.php
https://elt.oup.com/student/solutions/preint/grammar/grammar_04_012e?cc=global&selLanguage=en
https://www.grammar.cl/Games/Comparatives_Superlatives.htm
https://www.perfect-english-grammar.com/superlatives-exercise-1.html
https://www.perfect-english-grammar.com/comparative-adjectives-exercise-1.html
https://agendaweb.org/exercises/grammar/comparison/positive-comparative-superlative.htm
https://agendaweb.org/exercises/grammar/comparison/comparative-superlative-adjectives.htm
https://agendaweb.org/exercises/grammar/comparison/positive-comparative-superlative-write.htm
https://www.gamestolearnenglish.com/comparatives/
Prepositions of time:
https://www.perfect-english-grammar.com/time-prepositions-exercise-1.html
https://www.perfect-english-grammar.com/time-prepositions-exercise-2.html
https://test-english.com/grammar-points/a1/at-in-on-prepositions-time/
https://learnenglish.britishcouncil.org/grammar/a1-a2-grammar/prepositions-of-time-at-in-on
https://learnenglishteens.britishcouncil.org/grammar/a1-a2-grammar/prepositions-time