Thank you very much for helping me. I still have some doubts on a few sentences.I really hope you can have a look at them.

1)He has to choose a casket among (between?) three. Creditors are allowed to cut off bits of the debtor’s flesh. (Also: bits of flesh from the debtor?)
2)Life in Venice was very hard for the Jewish communities (OR: Living conditions were very hard for them OR they led a hard life?).Many among them practised moneylending at interest (OR and charged high interest rates?)
3)Real love comes from the eyes and goes beyond appearances.
4)All of Antonio’s ships are lost in the sea. (?)
5)They can inherit his property when he dies (after his death, at his death?). Shylock hopes that his daughter will die soon (will be soon dead?). He wishes his daughter’s death.
6)There is some good news (or a good piece of news) for Antonio and Jessica.
Portia, disguised as a judge, asks him to be merciful to Antonio.
7)In those days (at that time, during that time) Jewish communities were discriminated against. They couldn’t do all kinds of jobs (?) and were permitted to leave the ghetto (only?) at certain hours of the day only (?).
8) Jessica has gone away with Lorenzo, one of Antonio's friends (also: a friend of Antonio's).
9) Shylock can take a pound of his flesh on condition that not a single drop of Antonio's blood falls.
He won’t take Shylock’s property on condition that he converts to Christianity. (Not: becomes Christian?)

1. between is used when comparing 2 objects. Among is used when comparing more that two.

2. Any of those possibilities would be fine.

3. Goes beyond appearances
4. fine
5. Any of those would be correct.
6. Either would be correct.
7. Only following ghetto.
8. Either is fine.
9. Either is correct.