When a pupil goes to school (not A school) it is because “school” is used for its main purpose – learning. If we talk about a teacher, we say that he/she works at A school because working at a school is somehow not using it for its main purpose…
But what if a teacher just goes to (a) school. E.g. My mother is a teacher, she works at a school so every morning she goes to school – or to A school?
Thank you in advance.
If a person is a teacher, you can assume they work at a school.
You might hear "She works in a high school" or "He works at a private elementary school" or "She's at the new school on Elm Street" but not "My mother is a teacher and she works at a school." You would only hear it if it were not a school: My mother is a teacher, but she doesn't work in a school. She goes to tutor kids are are at home because of extended illness (or something like that).
Anyway, you would say "She goes to school around 6" or "She leaves for school very early" or whatever -- no "the" or "a."
I'm not a teacher, but I write for a living. Please don't ask me about 2nd conditionals, but I'm a safe bet for what reads well in (American) English.