Is there any difference between further and farther in the following two sentences?

　　下面两个句子中farther和further有什么区别吗?

　　She moved further down the train.

　　She moved farther down the train.

　　这两个词的根源都是一样的，正如上面的句子，这两个词的意思都是“去往更远的地方”，都是正确的。

　　Further is a much more common word, though, and is additionally used in various abstract andmetaphorical contexts, for example referring to time, in which farther is unusual, e.g.:

　　然而 ，Further这个词更为常见，可以用于各种抽象或者比喻的表达中，farther则不常见，如指时间上的进一步,比如：

　　without further delay

　　没有进一步的耽搁

　　Have you anything further to say?

　　你还有其他想说的吗?

　　We intend to stay a further two weeks.

　　我们打算再多呆两个星期。

　　Farthest 和 furthest也是同样的区别，比如：

　　the farthest point from the sun

　　离太阳最远的一点

　　The first team has gone furthest in analysis.

　　在分析中第一个团队走了最远。