When and Where do you use Apostrophes?
When and where to use apostrophes is the most asked question when wording invitations or on return address labels.
DO NOT use an apostrophe on your return address!
This the number one mistake made on invitations (See rule 1 below). On a return address is using an apostrophe on a last name:
- The Smiths is plural for “Smith” and means there is more than one person named Smith and the invitation is from them all. When in doubt, we like to use “The Smith Family”.史密斯家族是 “史密斯 “的复数，意思是叫史密斯的人不止一个，邀请函是他们所有人发出的。 如果有疑问，我们喜欢用 “史密斯家族”。
- The Smith’s (with an apostrophe before the s) is the possessive of “Smith” and indicates one person ownership.Smith’s（s前加撇号）是 “Smith “的占有式，表示一人所有。
- The Smiths’ (with an apostrophe after the s) is plural possessive and means the possession of more than one “Smith” of something (see Rule 2 below) like “The Smiths’ house is white.” 史密斯夫妇（带有s后面的撇号）是复数所有格，并且意味着一个以上的“史密斯”拥有的某个东西（见下文规则2），例如“史密斯的房子是白色的”。
So, the proper grammar for your return address is “The Smiths” or “The Smiths invite you …” as you are using the plural form of the name = Smiths, not possessive form (Smith’s or Smiths’), so no apostrophe, please!
DO NOT use an apostrophe to sign your names!
When signing your Christmas cards or thank you notes with your names:
“Happy Holidays from the Smiths””史密斯夫妇（一家）祝你节日快乐”
there is no apostrophe as you mean “plural” as the message is from all the people of the Smith family.
Grammar Rules and the Use of Apostrophes:
Rule 1. Do not use an apostrophe for the plural of a name.
Examples: We visited the Sanchezes in Los Angeles.
We visited the Sanchezes in Los Angeles.
Rule 2. To show plural possession, make the noun plural first. Then immediately use the apostrophe.为了表示复数占有，先把名词变成复数。然后马上用撇号。
Examples: the Changs’ house
the Millers’ golf clubs
the Strauses’ daughter
the Sanchezes’ artwork
the Halstons’ appointment
the Lemons’ books
the boys’ hats
the women’s hats
the actresses’ hats
the children’s hats
Rule 3. Use the apostrophe to show possession. Place the apostrophe before the s to show singular possession.用省略号表示占有。 将撇号放在s前，表示单数占有
Examples: one boy’s hat
one woman’s hat
one actress’s hat
one child’s hat
one woman’s hat
Ms. Chang’s house
NOTE: Although names ending in s or an s sound are not required to have the second s added in possessive form, it is preferred.虽然以s或s音结尾的名字不需要在占位形式中加上第二个s，但它是首选。
Mr. Jones’s golf clubs
Texas’s weather
Ms. Straus’s daughter
Jose Sanchez’s artwork
Dr. Hastings’s appointment (name is Hastings)
Mrs. Lees’s books (name is Lees)
Rule 4. Use the apostrophe where the noun that should follow is implied.在应跟的名词隐含的地方用撇号。
Example: This was his father’s, not his, jacket.
Rule 5. Use the apostrophe with contractions. The apostrophe is always placed at the spot where the letter(s) has been removed.在使用收缩词时使用省略号。撇号总是放在被删除字母的地方。
Examples: don’t, isn’t
You’re right.
She’s a great teacher.
Rule 6. With a singular compound noun, show possession with ‘s at the end of the word.对于单复名词，在词尾用’s表示占有。
Example: my mother-in-law’s hat
Rule 7. If the compound noun is plural, form the plural first and then use the apostrophe.如果复合名词是复数，先组成复数，再使用撇号。
Example: my two brothers-in-law’s hats
Rule 8. Use the apostrophe and s after the second name only if two people possess the same item.只有当两个人拥有相同的物品时，才在第二个名字后面使用引号和s。
Examples: Cesar and Maribel’s home is constructed of redwood. (共同所有权)
Cesar’s and Maribel’s job contracts will be renewed next year. (单独所有权)
Cesar and Maribel’s job contracts will be renewed next year.
(Joint ownership of more than one contract.共同拥有一份以上的合同)
Rule 9. Never use an apostrophe with possessive pronouns (show that something belongs to someone): his, hers, its, theirs, ours, yours, my, whose. They already show possession so they do not require an apostrophe.千万不要在占有性代词（表示某物属于某人）上使用撇号：他的、她的、它的、他们的、我们的、你的、我的、谁的。它们已经表示占有，所以不需要用撇号。
Examples: The white house is theirs.
The dog lost its toy.
Rule 10. The only time an apostrophe is used for it’s is when it is a contraction for it is or it has.只有当它是it is或it has的收缩词时，才会用撇号。
Examples: It’s a nice day.
It’s your right to refuse the invitation.
It’s been great getting to know you.
Rule 11. The plurals for capital letters and numbers used as nouns are not formed with apostrophes.用作名词的大写字母和数字的复数不使用撇号。
Examples: She consulted with three M.D.s.
BUT
She went to three M.D.s’ offices. (The apostrophe is needed here to show plural possessive.)
She learned her ABCs.
the 1990s not the 1990’s
the ’90s or the mid-’70s not the ’90’s or the mid-’70’s
She learned her times tables for 6s and 7s.
Exception: Use apostrophes with capital letters and numbers when the meaning would be unclear otherwise.当含义不明确时，可使用带大写字母和数字的撇号。
Examples: Please dot your I’s. (You don’t mean Is.)
Ted couldn’t distinguish between her 6’s and 0’s. (You don’t mean Os.)
Rule 12. Use the possessive case in front of a gerund (-ing word).在动名词（-ing词）前使用占位式。
Examples: Alex’s skating was a joy to behold.
This does not stop Joan’s inspecting of our facilities next Thursday.
Rule 13. If the gerund has a pronoun in front of it, use the possessive form of that pronoun.如果动名词前面有代词，就用该代词的占有式。
Examples: I appreciate your inviting me to dinner.
I appreciated his working with me to resolve the conflict.