incorrect sentence! "My car's door is broken" I heard the following grammar rule for first time in an English learning video in youtube. Please, your advice. We don't use ('s) with things so, "My car's door is broken" is incorrect but "The door of my car is broken" is correct As well as, we don't use "of" with people so, "This is the house of my sister" is incorrect but "This is my sister's house" is correct !