Director of Operation Dept.
其实主任有多种说法，head/director/chief都可以说的，用director听上去大些
其他主任的一些说法供参考：
teacher in charge of a class
班主任
director of the general office
办公厅主任
director of a workshop
车间主任
director of the department of translation and interpretation
翻译室主任
chief accountant
会计主任
chief of teaching and research section
教研室主任
head of the neighbourhood committee
居民委员会主任
dean; dean of the faculty
系主任
Minister in charge of the State Planning Commission
国家计划委员会主任
Director of the General Political Department
总政治部主任
director of teaching affairs
教务主任
dean of personnel
人事处主任
dean of studies
教导主任
a department head
部门主任
director of the office of foreign affairs
外事办公室主任
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