•Do you know any of the boy's friends' name ? It would be correct if you use NAMES in plural. "Do you know any of the names of the boy's friends?" might be easier to understand, but they both mean the same. There is one boy, he has several friends, and you want to know their names. To say it without the "boy's" would be "Do you know any of the names of the friends of the boy?" •Do you know any of the boy friends' name ? This is wrong. "boy friends' names" doesn't have any definitive meaning. If you told it to someone they might either understand it as "the names of the boyfriends" or "names of the boy's friends" •The boy's car's colour is beautiful. IE: "The color of the car of the boy is beautiful" It would be correct, but I haven't heard it being used. "The color of the boy's car" I think is much easier to understand. •The boy car's colour is beautiful. Similar to number 2, this doesn't make much sense. You want to say that the car is owned by the boy. To say that, you should use "The boy's car" to signify whose car it is. I sometimes like to watch videos on youtube about languages, and the people at EngVid have a lot of handy videos, like for example this on the use of apostrophes: https://www.youtube.com/watch?v=7LwamFnWGVA I hope I was able to make myself understood. Have a nice day