请问,it's not yours算不算是it is not yours的缩写?

请问,it's not yours算不算是it is not yours的缩写? it is not yours的缩写是神马 Is that yours?No,it's not () .It's (). It is not yours,it is mine. 1.The camera is not yours.It’s ______. whose pen is this?is it yours?no it's not mine.maybe it's() 王老师,Excuse me .Is this ( yours) (你的) hat?No,it's not mine.(我 IF IT IS NOT YOURS,IT ALSO ALWAYS IS 1.Whose bike is it ( )(your/yours) NO,it's not( )(my/mine) ( "is this coat yours?No,it's not mine."此句中为什么要用yours和mine? Look at the book,it's not mine,and it's not yours,so it must it is not的缩写是it isn`t还是it`s not?