freeadj.自由的；免费的；畅通的；没有…的；未使用的；空闲的；随意的v.释放；使自由；使摆脱；解除；使可用于(某目的)adv.免费地；自由地free riden.自由通过；不劳而获的东西；搭便车vi.不劳而获

1. Find the number of degrees of rotation of the lower member.
   求下杆转动的度数。
2. It was the first time anyone had ever derived the observed number of dimensions from first principles.
   这是有史以来第一次有人从第一原理导出这个维度数值。