把它还原成陈述句: this book is ( ) you borrowed from library
很显然this book是句子主语,the one作表语(省略that,you borrowed from library )定语从句修饰the one
把它还原成陈述句: this book is ( ) you borrowed from library
很显然this book是句子主语,the one作表语(省略that,you borrowed from library )定语从句修饰the one