《语音篇》为基础阶段辅助教材，其余三篇主干教材依次按基础、初级、中级三个等级设置。
The Phonetics book is a supplementary one at the starter's level, while the other three are designed for learners at starter's, elementary and intermediate levels respectively.
《语音篇》为基础阶段辅助教材，其余三篇主干教材依次按基础、初级、中级三个等级设置。
The Phonetics book is a supplementary one at the starter's level, while the other three are designed for learners at starter's, elementary and intermediate levels respectively.
应用推荐