The [ju:] diphthong. This combines the y, y, uh-y, Y consonant sound with the oo, closed oo. Ew, ew. As you can see, the lips come in and round. The tongue also shifts. On the y, it's like that, up against the teeth, y, y, the bottom teeth, and it then shifts: yy-oo, ew. So it comes away from the front a little bit because in the oo vowel it's fattening up a little bit in the back, which means there's not as much tongue to have room to curl a bit like that against the teeth. So though it is still touching the teeth, it comes back like that. Ew, eeew.
[ju:]是一个复合元音，由辅音y, y, uh-y 连接oo构成，发woo时口型紧缩。Ew, ew. 正如你所见，发音时嘴唇是向内聚拢成圆形的。舌头同样有变化。发y这个音的时候，舌头是这样顶住牙齿，y, y, 是顶住下边的牙齿，然后它开始移动：yy-oo, ew. 舌头从口腔前部略微移开，因为在发元音oo时，舌头会在口腔后部平展，也就是说舌头卷曲起来顶住牙齿的部位会减少。所以说虽然舌头仍然触及牙齿，它却是在向后移动。Ew, eeew.
There are few true beauties.