但是昨天我发true,rue,roof给native speaker听,说不太对头。但是我发raise他说就对。所以我还在琢磨这个问题,现在的想法是,R之所以被称为美音里最难的一个音(Rachel/俺厨师都有说),可能与它在不同的position发音不同有关。
1. initial position as a consonant as in raise, rose.
2. after vowel, as a rhotic feature as in hair, car
3. part of consonant cluster as in true, drew, great, strong, etc.
Looking forward to your post, 永学哥。