Many people believe “between” should be used for choices involving two items and “among” for choices that involve more than two items. However, it’s not that simple.
若做一個簡單劃分，between 是講兩者之間 (e.g. I am standing between the two trees)。 among 是三者或多是於三者, 即是一群人或物之間 (e.g. I am standing among the trees)。
Here’s the difference: you should use use the word “between” when you are talking about distinct, individual items even if there are more than two of them (e.g. She chose between MIT, Harvard, and Stanford, three very different universities).
不過，between 這字也會用於多於兩者之間。當一些人或物當中，要比較或強調其中任何兩者以上的不同，便要用 between 而不用 among 了 (e.g. The differences between English, Chinese, and Arabic are significant.)。
On the other hand, you use “among” when you are talking about things that aren’t distinct items or individuals (e.g. She chose among the top universities around the world).
然而，among 是用於在一群人或物之間而沒有去區分這些人或物 (e.g. I found the letter among his papers.)。