From: www.grammar.net/

According to Grammar.net, the most common grammar mistake in English is a misplaced or missing apostrophe! Do you believe this? I’m not sure I do, there are just so many grammar mistakes out there, but I do know that learning to use apostrophes correctly in English is very important and many ESL learners make mistakes by misplacing apostrophes. So this is definitely a topic worth discussing.

You can see in the infografic above the 10 most common words in English with misplaced or missing apostrophes. Memorize these words with their apostrophes in the right places so that you never misspell them again!

Now take a look at these general rules for the use of apostrophes in English:

Use an apostrophe when making a contraction. The apostrophe is always placed at the spot where the letter(s) has been removed.
Example: You are right. = You’re right.

Use an apostrophe to show possession. Place the apostrophe before the last s in possessive words.
Example: That is the hat that belongs to my mom. = That is my mom’s hat.

To show plural possession, make the noun plural first, then add an apostrophe or apostrophe + s.
Examples:
I’d like to by three children’s hats.
That is the Joneses’ house.

Never use an apostrophe with possessive pronouns: his, hers, its, theirs, ours, yours, whose. These words already show possession without an apostrophe.

Use an apostrophe with” it’s” when it is a contraction for “it + is” or “it + has.”
(The possessive for of the word it, “its,” does not have an apostrophe.)
Examples:
It is a nice day. = It’s a nice day.
It has been nice seeing you. = It’s been nice seeing you.

Here is a quick practice exercise for review. Decided where to add apostrophes in these sentences. You can find the answers below.

1. Our neighbors car is very old, and its about to fall apart.
2. The mother did not hear her childrens yells for help after falling out of the tree.
3. Its such a beautiful day that Im going to the beach.
4. In this store the girls and boys clothing is on the first floor and the mens and womens clothing is on the second floor.
5. Theyre not afraid to go out into the woods to camp over night.
6. Dont forget thats my hat, not yours.
7. Wouldnt you like to have some dinner with us tonight?
8. The police officer wasnt able to get the robber.

Answers:
1. Our neighbor’s car is very old, and it’s about to fall apart.
2. The mother did not hear her children’s yells for help after falling out of the tree.
3. It’s such a beautiful day that I’m going to the beach.
4. In this store the girls’ and boys’ clothing is on the first floor and the men’s and women’s clothing is on the second floor.
5. They’re not afraid to go out into the woods to camp over night.
6. Don’t forget that’s my hat, not yours.
7. Wouldn’t you like to have some dinner with us tonight?
8. The police officer wasn’t able to get the robber.