According to the shape of the lips, vowels can be classified into close vowels, semi-close vowels, semi-open vowels and open vowels. A: 正确 B: 错误

中国大学MOOC: Pure vowels can be classified into three categories: front vowels, central vowels and back vowels. The two vowels/ɜː/ and /ə/ are classified into ______ vowels because they are made with the middle part of the tongue being raised.

中国大学MOOC: How can you distinguish between front vowels, central vowels, and back vowels?

There are vowels in English.

Among the 20 vowels in RP, there are 12 pure vowels and 8 diphthongs. A: 正确 B: 错误

中国大学MOOC: Among the 20 vowels in RP, there are 12 pure vowels and 8 diphthongs.

Which of the following statements is/are correct about vowels? A: Vowels are produced without significant constriction of the air flowing through the mouth. B: There are 28 vowel sounds in English. C: Vowels refer to the sounds in spoken language that are made with no obstruction of air flow in the mouth. D: All vowels are voiced.

There are ______ pure vowels in English.

What are the features of vowels and consonants?

What is the difference between consonants and vowels? A: Vowels have a longer duration in actual production. B: Air stream is obstructed in producing consonants. C: Consonants all involve the vibration of the vocal cords.. D: Vowels are louder than consonants.