major axis

例句：

1. 1. The major axis of the planet is its rotational axis.
   行星的主要轴是它的旋转轴。
2. 2. The new model car has a major axis that runs through the center of the engine.
   新款汽车有一个贯穿发动机中心的主轴。
3. 3. The scientists determined the major axis of the elliptical orbit.
   科学家们确定了椭圆轨道的主要轴。