题目内容：

is this book＿you borrowed from the library?A that B which C the one D it
可是我不明白选它的理由,

优质解答

疑问句还原
你会发现是
this book is _____ you borrowed from the library?
句子缺少一个先行词而不是关系词
所以C 这里关系词that、which 可以省却因为先行词是做宾语