"做代理教师" can be translated into English as "to work as a substitute teacher" or "to serve as a temporary teacher".
"Substitute teacher" is a common term used in educational contexts to refer to someone who fills in for a regular teacher when they are absent.
"Temporary teacher" also conveys the idea of working in a teaching role for a limited period or as a replacement.
Both expressions are accurate and widely understood in English-speaking environments.