英语语法分析

The earth is nonspherical and has a tilted axis.

地球不是球形的并有一倾斜的转轴。

A gradient in the gravitational forces acting on different parts of a nonspherical object.

作用于非天体物体不同部分的引力梯度。

The orbit variation in one day under the nonspherical perturbation is shown and the motion of the orbit plane is computed.

计算给出了一日内的卫星轨道，反映了在地球非球形摄动下轨道的变化情况，且对轨道面的进动进行了计算。