英语语法分析

A comet is at aphelion when it is farthest from the sun.

彗星离太阳最远时就是在它的远日点上。

The Q is - do you mean Pluto in its aphelion or perihelion ?

我的问题是，冥王星此时是在近地点还是远地点？

But it's not that simple either, because the dates of the perihelion and aphelion are also shifting.

但这并不是简单的一件事情，因为近日点和远日点的日期都会变换。