Monophthong vowels, compound vowels and nasal terminal vowels as well as the rates of every error type and the causes of the high-rate types have been discussed.

• 按照单元音韵母、纯元音复合韵母和鼻韵尾复合韵母的分类，统计了三类韵母中的偏误比率，分析了偏误率较高的几类偏误的原因。