试题题干
Fill in each of the following blanks with a word or an expression.
According to the state of the 
,vowels are divided into oral vowels and nasal vowels.
参考答案
试题解析
According to the state of the velum ,vowels are divided into oral vowels and nasal vowels. 根据软腭的状态，元音被分成口腔元音和鼻腔元音。