Hello. 1. a. This city has less beautiful bridges than Paris. b. This city has fewer beautiful bridges than Paris. 2. a. I have less difficult problems than you. b. I have fewer difficult problems than you. 3. a. They drink less fresh water than the city people. Question 1 : I think these are all correct. But they have different meaning because 'less' is adverb and modifies 'adjective', 'fewer' is adjective and modifies 'noun'. Therefore, in 1(a) and 2(a) sentences, though 'bridges' and 'problems' are countable nouns, 'less' modifies 'beautiful' and 'difficult'. In 1(b) and 2(b), 'fewer' modifies 'bridges' and 'problems' Am I right? Question 2 : As 'less' modifies 'adjective' before 'noun', 'noun' after 'adjective' can be both 'countable noun' and 'noncountable' such as 1(a) 2(a) and 3(a). Am I right? Thank you always~.