Hum and lip tremolo challenge high pitch song practice

Hum and lip tremolo challenge high pitch song practice, can not pick up the treble try to sing with the lip trill, until it is no longer difficult

https://node.kg.qq.com/play?s=AlSatfAm3DSUgAE0&shareuid=6b9f9b84252f33823c&topsource=a0_pn201001006_z1_u926102498_l1_t1606472101__