有關student's 同 student'既問題

Possessive Form:

Singular noun not ending in s, add apostrophe + s,
friend -> friend’s
e.g. my friend’s name = the name of my friend

Singular noun ending in s, add apostrophe + s,
bus -> bus’s, boss -> boss’s
e.g. my boss’s daughter = the daughter of my boss

Plural noun ending in s, just add apostrophe.
friends -> friends’ buses -> buses’
e.g. my friends’ names = the names of my friends

Plural noun not ending in s, add apostrophe + s
children -> children’s men -> men’s
e.g. my children’s names = the names of my children

After surname ending in s, we can add apostrophe + s or just apostrophe
For example, Dickens is the surname.
Dickens’ book or Dickens’s book = the book of Dickens

Be careful! It may have extra s omitted if it would cause an awkward series of sound.
Moses ~ Moses’ wife

We prefer to add only apostrophe when the word following begins with an s or a z sound.
Chris’s enthusiasm, but Chris' zeal
hostess’s idea, but hostess’ sake

We usually add only apostrophe to classical names ending in s
Pythagoras’ Theorem Archimedes’ Principle

Note the difference:
John and Mary’s children (one lot of children: John and Mary are their parents.)
John’s and Mary’s children (two separate lots of children: John’s and Mary’s)

The Chan's family可說The Chans-姓陳那家人
The Chans'-姓陳那家人的

when the noun originally ends with s, the ' will be outside s, like: the two students' homework are done; the three books' front pages are attractive. however, beware that if the noun does not end with s, even if it is a plural noun, the ' is still inside s, like: the government is people's belongings.