He didn't know ( )book he'll choose ,A,B

问题描述:

He didn't know ( )book he'll choose ,A,B
什么时候可以用whose

A
He didn't know ( which ) book he'll choose 为宾语从句,他不知道他要选那本书
whose用在定语从句里,the house whose windows face south,whose翻译成···的,窗户朝南的房子.