Hello guys, Welcome to Africa's Largest Video Search Engine, and you are watching 16共振 机械振动 高中物理. and this video is uploaded by 凌海燕 at 2019-07-08T13:00:54-07:00. We are just promoting this video only for entertainment and educational purpose only. I hop you like our Video Search Engine. [hBrCakrZPFM]