1 'among' and 'between'
If you are among a group of people or things, you are surrounded by them.
- James wandered among his guests.
- Among his baggage was a medicine chest.
You do not say that you are 'among' two people or things. You say that you are between them.
在两个人或物体当中，使用between， 大于两个的人或物体当中，使用among.
- Myra and Barbara sat in the back, the baby between them.
- She put the cigarette between her lips.
- The island is midway between Sao Paulo and Porto Alegre.
2 dividing
You can say that something is divided among or between a group of people. There is no difference in meaning.
在表达‘分开、被分开’的意思时，among或between都可以使用。
- ...his estate, which he divided among his brothers and sisters.
- Different scenes from the play are divided between five couples.
Note that the form amongst is somethings used, but is more formal than among.
- I heard that flour was being distributed amongst the citizens.
3 differences
You do not use among when you are talking about differences. You do not say, for example, 'I couldn't see any difference among the tree chairs'. You say 'I couldn't see any differences between the three chairs'.
使用between来表达‘不同’，而不使用among。
- There was an important difference between the political analytics and the military ones.
- For the 1997 election, while experts could tell the difference between the three main parties, the computer did not.
