Facing challenges,the roles of English teacher in middle school should covert their roles：from the performers of fixed class models to designers of new class models; from the language initiators to cultivators of language skills and disseminators of culture.
参考例句
教师要适应这些变化,就应实现角色转换,由文化知识的传授者、知识学习的指导者转变为学生学习的协助者；
In order to accommodate these changes,the teachers should convert their roles in the teaching:from the initiator of culture and mentor of knowledge to assistants of students ;