When to Use Apostrophes
The rules about when to use apostrophes can be summarised:
a. To replace missing letters (e.g.,
aren't).
b. To show possession (e.g., Sarah's
jumper).
c. In expressions such
as 3 months' wages.
d. In the plurals of
abbreviations, letters and numbers (e.g., 6's and 7's).
Don't Add Your Own Apostrophe to a Plural Word
Unless it is covered by one of the categories above, an apostrophe should not be used. However, words that end in the letter
s seem to attract apostrophes. The plural of words ending in vowels (e.g.,
video, patio) are extremely prone to this error. This is a very common mistake and is considered a grammatical howler.
Examples:
Dog's look up to us, and cat's look down on us. I prefer pig's – they
treat us as equal's. (badly transcribed version of a Sir Winston
Churchill quote)
Anteater's prefer termite's to ant's. 
Pearl's melt in vinegar. 
Rent two adult video's for the price of one. 
Three large male lion's approached the 4x4.
(lions
)
Snow White and the Seven Dwarf's.
(Dwarfs
Actually, you could write "Dwarves" too — both are correct plurals of dwarf.)

should be cameras
(motorway sign)

should be "Ministers are very...
(newspaper article)
Their board genuinely stated: "Open seven day's a week and weekend's".

(days / weekends
)
She fly's to New York regularly.
(flies
)
There are 24 applicant's waiting in the coffee room.
[correct the example] (do
not use an apostrophe just because a word ends in s)
|
DO NOT USE AN APOSTROPHES JUST BECAUSE A WORD ENDS IN S
In English, the overwhelming majority of words show their plurals by adding s.
Do not throw in your own apostrophe.
As fruit and vegetable stalls often display this error, it has come to be known
as the grocers' apostrophe.
2
melon's for a pound
1 kg of apple's
for a dollar 

signs on market stalls are often
littered with
apostrophe errors
|
|