Apostrophes serve two functions in English: showing possession (John's book) and marking missing letters in contractions (it's = it is). Misusing them — especially the infamous "it's vs its" confusion — is one of the most noticed written errors in English.
Practice
Where does the apostrophe go? "The report of the two managers" → "the two ___"
Have you met thenew teacher? She's brilliant.
Put the words in the correct order:
"___ raining outside. Bring an umbrella." Which is correct?
Iseen that film three times already.
Put the words in the correct order:
The company changed ___ logo last year.
been decided that the office will close early today.
Put the words in the correct order:
Which sentence shows that the toy belongs to one dog?