major semi-axis

例句：

1. 1. The major semi-axis of the planet is located at the equator.
   行星的主要半轴位于赤道。
2. 2.The construction of the new bridge involved major semi-axis adjustments.
   新桥梁的建设涉及主要半轴的调整。
3. 3.The scientists discovered a major semi-axis that could explain the phenomenon.
   科学家们发现了一个主要半轴，可以解释这一现象。