I am 'The French' thank for reply, but I would like to know if is it a English grammar rule this ' ?
I am thinking about the use for 's in the possessive form.
Waiting for your answer, pehaps you have it in your knowledge.
Have nice day.
Many learners find the apostrophe confusing with good reason. It can be used to denote possession: 'This is Brian's car' for example. It can, as Soup has said, replace a vowel in a contraction: 'That's a good idea' (That is a good idea) for example. Where confusion often occurs is when learners mix up the two: 'This is Brian's car, Brian's a good driver.' In the first Brian's the apostrophe denotes possession and in the second it represents a contraction of Brian is. I try as far as possible not to use contractions with learners until they are more advanced.