a mass of bobbing heads

• 人头攒动

a mass of bobbing heads的用法和样例：

例句

1. Every corner of the ship was thronged.
   船上每个角落都是人头攒动。
2. In the twenties, I was very happy, while crowding with a mass of people, and eating a Cornet on the bus.
   二十岁的时候，挤在人头攒动的公共大巴上，吃着甜筒，挺开心。