vowel的意思是：名词：元音；元音字母，形容词：母音的。
vowel的例句有：
1、Each language has a different vowel system.
2、The alphabet might be more rational if all the vowels came first .
3、The word commences with a vowel.
4、Vowels possess greater sonority than consonants.
5、The progress of vowel loss can be divided into two stages.
6、Thus, the third for loop finds two additional vowels.
