and/u/ 1./u/is the highest back vowel,so the raised part of the tongue for//is higher than that for/u/ 2.the part of thetongue raised for/u/is not as back as that for/u/ 3./u:/has quite strong lip rounding while the lips are only slightly rounded for/u/. /3:/and/p/ isa mid-back vowel For the tongue is retracted and almos flat in the mouth The vowel is almost fully back and has quite strong lip-rounding./ is a low vowel.The lips are slightly rounded.//is a difficult vowel for the Chinese learners.Many of them use a shortened version of/:/as its substitution.To ensure correct pronunciation,it is important to make the following distinction between these more open for// 2.:/has quite strong lip rounding while the lips are only slightly rounded for/ la:/and /A/ The /is made by lowering and flattening g the tonguc cavity.It is a low vowel.but not as back as other back vowels Englishis quite different fron other vowels in this group in that it is more like a central vowel than a back vowel (see the vowel chart)./A/is made with the tongue in the approximate middle of the mouth,perhaps shifted back slightly.It is lower than the other central vowels/3/and A/.The lip position is neutral.It is important for the leamners to make a clear distinction between/a/and /in their pronunciatior and / u /: 1. /u:/ is the highest back vowel, so the raised part of the tongue for /u:/ is higher than that for / u /; 2. the part of the tongue raised for / u / is not as back as that for /u:/; 3. /u:/ has quite strong lip rounding while the lips are only slightly rounded for / u /. / ɔ:/ and / ɒ/ / ɔ:/ is a mid-back vowel. For its production, the tongue is retracted and almost flat in the mouth. The vowel is almost fully back and has quite strong lip-rounding. /ɒ/ is a low vowel. The lips are slightly rounded. / ɒ/ is a difficult vowel for the Chinese learners. Many of them use a shortened version of / ɔ:/ as its substitution. To ensure correct pronunciation, it is important to make the following distinction between these two vowels: 1. / ɒ/ is a low vowel while / ɔ:/ is a mid vowel, so the mouth is more open for / ɒ/, 2. / ɔ:/ has quite strong lip rounding while the lips are only slightly rounded for / ɒ/. /ɑ:/ and /Λ/ The /ɑ:/ is made by lowering and flattening the tongue in the oral cavity. It is a low vowel, but not as back as other back vowels in English. /Λ/ is quite different from other vowels in this group in that it is more like a central vowel than a back vowel (see the vowel chart). /Λ/ is made with the tongue in the approximate middle of the mouth, perhaps shifted back slightly. It is lower than the other central vowels /з:/ and /Λ/. The lip position is neutral. It is important for the learners to make a clear distinction between /ɑ:/ and /Λ/ in their pronunciation