What is the best way to explain how to choose between "its" and "it's"?

Question

Probably one of the most frequent grammar mistakes in the English language is:> The dog sat on it's mat.Since spelling checkers don't catch it, and it is even logical, since you would correctly write:> The dog sat on Fluffy's mat.What is the best way to explain to a learner of English how to choose between *it's* and *its*?

Answer 1

Remember that an apostrophe often replaces a letter. Just like in “they’re” the apostrophe replaces the “a” in “they are,” the apostrophe replaces the “i” in “it is.” Therefore “it is” equals “it’s.”

To remember the possessive “its,” try replacing it with a gender-specific “his” or “her.” Since we would never put an apostrophe in “his,” we also wouldn’t put one in “its.”