this is 与this's 的区别?在哪些情况下有不同的含义或用法?

whose 与who's的区别-----------caclulator is this,Mary?It's mine用哪一个呢? this is 与this's 的区别?在哪些情况下有不同的含义或用法? this is 与this's 的区别?在哪些情况下有不同的含义或用法? this is和this are的区别 It's your book.与This is your book.的区别? this is 与these are 的区别,该怎样讲解 this is 与these are here is 与 this is 区别是? is this your brother?的回答与is this girl your sister?的回答的区别 whose pen is this与whose is this pen的区别 This is we common desire.与This is our common desire.的区别 Is this the 与 Is this a 的区别在哪里 what is this和what is that的回答与区别 what are they和what are these/those的回答与区别.是this is /that is.还是it is /it's是they are these are /those are Is this your book?与Is this book jim's?区别Is this your book?Is this book jim's?这句可以写成Is this jim's book?如果不可以,是不是表达具体是哪个指定人的东西时就要把人放在东西后面呢? Is this car 和 Is this the car 的区别 this is it 和is this it的区别 this is ...和it is...的区别 what's this in English?It's a pen.为什么不能说是this is a pen.?详细!this is 在哪能用?二者的区别是什么?谢谢啊! 如何回答 Whose is this 是说It's ...还是 This is...有何区别同理。Is this...是回答It's 还是 This is...有何区别？