Teaching assistants need different time according to their academic qualifications. Teaching assistants with a bachelor's degree or below can apply for professional and technical positions normally after two years, and can make an exception for less than two years. After graduating from full-time graduate school, I worked as a teaching assistant for three years and so on.

Class tutor is equivalent to the head teacher in high school, but it is called class tutor in university. The tutor is responsible for guiding and educating the students in this class! The class assistant is the tutor's assistant, assisting the class tutor's work.