How are the English vowels classified? 英语的元音如何分类?请

正确答案：Vowels are the sounds in the production of which no articulators come very close together and the air stream passes through the vocal tract without obstructions．The English vowels are divided into two large groups：monophthongs(pure vowels)and diphthongs(gliding vowels)．The monophthongs are further divided into several types according to different criteria：by the height of the raised part of the tongue；by the part of the tongue raised；by the length of the vowel；by the position ofthe lips；by the degree oftenseness． 在发音过程中发音器官并不彼此靠近气流通过声道时不受任何阻碍此时发出的音叫元音。 英语的元音分为两大类即单元音和双元音。其中单元音按照不同标准又分成若干类：按舌的隆起部分的高度；按舌头隆起的部位；按元音的长度；按唇形；按紧张程度。
Vowelsarethesoundsintheproductionofwhichnoarticulatorscomeveryclosetogetherandtheairstreampassesthroughthevocaltractwithoutobstructions．TheEnglishvowelsaredividedintotwolargegroups：monophthongs(purevowels)anddiphthongs(glidingvowels)．Themonophthongsarefurtherdividedintoseveraltypesaccordingtodifferentcriteria：bytheheightoftheraisedpartofthetongue；bythepartofthetongueraised；bythelengthofthevowel；bythepositionofthelips；bythedegreeoftenseness．在发音过程中,发音器官并不彼此靠近,气流通过声道时,不受任何阻碍,此时发出的音叫元音。英语的元音分为两大类,即单元音和双元音。其中单元音按照不同标准又分成若干类：按舌的隆起部分的高度；按舌头隆起的部位；按元音的长度；按唇形；按紧张程度。