Réponse :
1. Today the Thames is less polluted / more polluted (les 2 marche cela depend du sense) than in Victorian times.
2. Today the Thames is as polluted as in Victorian times.
c. Today living conditions are more acceptable than in Victorian times.
In Victorian times, living conditions were less acceptable than today.
pour les 2 derniers tu n'a pas precisé l'adjectif :))
