Apostrophes are used to show possession. However, you do not use an apostrophe after a possessive pronoun such as my, mine, our, ours, his, hers, its, their, or theirs. For example:
Read more at http://grammar.yourdictionary.com/grammar-rules-and-tips/5-most-common.html#FVgk9FeOQezHUWZP.99
My name is Craig, and I've been teaching English for many years. I initially created this site for my students, but all English learners are welcome. I hope you find something helpful to you. Feel free to leave suggestions or ideas in the Comments section under any entry.