In Numbers^x, Countable nouns^x, Prepositions^x

Starstuff wrote: "Instead, they have watched the system become deformed over the years by fear of litigation , by insurance costs, by rising competition, by billowing bureaucracy and even by improvements in technology that introduce new risks even as they reduce old ones." Why isn't it "by the...

Hello, could someone help me with the questions about the word mountain? The prepositions used: Do you go skiing (in? (on?)) the mountain? JT: means the area where the mountains so you go skiing IN the mountainS. >> If you live in a house (in?) (on?) the mountain,can you tell people...