英语语法分析

Sometimes, they happen to see the orbits of exoplanets edge-on. In those cases, the planet alternately shows more of its dayside and then more of its nightside as it circles its star.

有时，天文学家们碰巧从侧面观察到系外行星的轨道，在这种情况下，行星在围绕恒星旋转的时候就会交替地呈现出有时光面较多、有时暗面较多。