试题题干
Fill in each of the following blanks with a word or an expression.
According to the shape of the lips, we can classify vowels into rounded vowels and 
vowels.
参考答案
试题解析
根据嘴唇的形状，我们可以把元音分类成圆唇元音和不圆唇元音。
Fill in each of the following blanks with a word or an expression.
According to the shape of the lips, we can classify vowels into rounded vowels and vowels.
根据嘴唇的形状，我们可以把元音分类成圆唇元音和不圆唇元音。