-----------------------------------
担任の先生， たんにんのせんせい
1. class teacher, homeroom teacher, home room teacher, form teacher
班主任，班主任，班级导师，班级教师
は
1. indicates sentence topic
2. indicates contrast with another option (stated or unstated)
3. adds emphasis
指示句子的主题；表示与另一选项（无论是否明确提及）形成对比；表示强调
