英汉例句双语例句The Laws of Planetary Motion Kepler's First Law: The orbits of the planets are ellipses, with the Sun at one focus of the ellipse.行星沿椭圆轨道绕太阳运行，太阳位于椭圆的一个焦点上。 对任一个行星说，它的径矢在相等的时间内扫过相等的面积。kepler's law of planetary motion更多例句词组短语短语Kepler 's law of planetary motion 开普勒行星运动定律kepler's law of planetary motion更多词组