Hello! Can you please tell me if the 'a' has to be omitted with nouns such as 'boarding school' and 'summer camp' or if it would also be acceptable to use it like with most nouns? For example. 1A. My parents sent me to boarding school/ summer camp. 1B. My parents sent me to a boarding school/ summer camp. 2A. She is at boarding school/summer camp. 2B. She is at a boarding school/summer camp. I have heard the version without 'a' many times but sometimes, certain structures, sound weird to me if I don't include 'a'. Can you please explain this to me? Thank you very much!