"I worked as a teacher at a high school."
I did a little research and found that 勤める (つとめる) verb is used (among other meanings) as "to serve (as)" meaning that you can specify what kind of work (position) the subject was doing, contrary to 働く (はらたく) that only indicates that a job was being done, but not i you were doing a surgery or giving a lecture.
Please any native or skilled japanese learner can confirm this?
When you touch on the English versionn to see suggestions, it shows the particle で as a translation for "as a (teacher) ", and を as a translation for "at a (high school)"... But if you do like that it says it's wrong and the correct translation is the exact opposite? I'm confused Duo.