小测验：选择正确的单词

1. axis of rotation
   旋转轴，自转轴，回转轴线
   
2. coordinate axis
   坐标轴
   
3. major axis
   长轴
   
4. minor axis
   短径，短轴
   
5. optic axis
   光轴，眼轴
   
6. principal axis
   主轴线，光轴
   
7. semimajor axis
   半长轴
   
8. semiminor axis
   (椭圆的)半短轴
   

1. Moving or directed away from a center or axis.
   从中心或轴移开或离开的。
2. The earth spins on its axis.
   地球绕地轴旋转。
3. The earth revolves Both round the sun and on its own axis.
   地球既公转又自转。
4. It turns on its own axis.
   它环绕其轴而转动。
5. The earth rotates on its axis once every 24 hours.
   地球每24小时依其轴心自转一次。

　6个名词解释