Farther and further are both adverbs that indicate distance. The main difference between the two is that farther refers to physical distance, while further refers to an extension of time or degree.

「Farther」 和 「further」 都是表示距离的副詞。兩者的主要區別在於，「farther」 指的是物理距離，而 「further」指的是時間或程度的延伸。
Here are some examples to illustrate the difference:
以下是一些例子來說明區別：

Farther:

• The store is farther from here than I thought. 這家商店離這裡比我想的遠。
• She threw the ball farther than anyone in the park. 她把球扔得比公園裡任何人都遠。

Further:

• We need to discuss this further before making a decision. 我們需要進一步討論才能做出決定。
• His behavior has caused further problems for the team. 他的行為為團隊帶來了更多問題。

In general, it is more common to use “farther" when referring to physical distance and “further" when referring to an extension of time or degree. However, in some cases, the two words can be used interchangeably. For example, you can say “The store is further from here than I thought," or “His behavior has caused farther problems for the team."

通常而言，在提到物理距離時更常用 「farther」，在提到時間或程度的延伸時更常用 「further」。然而，在某些情況下，這兩個詞可以互換使用。例如，你可以說 「The store is further from here than I thought」，或者 「His behavior has caused farther problems for the team」。