Sorry, this will the last question to finalize this post. When I was in college in Canada, one day I called my Canadian friend to ask if we didn't have to go to school the next day as it was a national holiday.(I don't remember exactly what kind of holiday it was) - and he said "It's a holiday, but school is happening"
1. By "school", did he mean generalization of school or school with the original purpose of school - studying?
2. If I don't have to consider original purpose and it was "generalization", then when can you use the singluar form "school" and when for the plural form of "schools"?
You normally don't say "Zoo is for watching animals." but "Zoos are for.." for the general idea of zoo. Or doesn't it have fixed and fast rule? It seems confusing as sometimes you can use "church" or "churches" for any random cases of general idea of church. Do I have to tell Koreans that there is no rule for singular or plural in general idea of nouns?