1如果像你那样选句子是这样的is this book you were talking about yesterday.变为肯定this book is you were talking about yesterday. 在系动词后少了先行词.所以加定冠词.才能变为 this is the book (that/which)you were talking about yesterday.
2.on sunday在星期天 on a sunday在某一星期天.是泛指.
3.你可能写错了,这道题应该选A 两空都不填.因为复数名词表示一类.
4.因为有only 还表示肯定.所以不用few
5. belong to 的宾语只能是人称代词宾格或名词.而whose是形容词性物主代词或相当于所有格所以不选.对比下面两句子
This book belongs to me.(正确)
Thisbook belongs to mine(错误)
6.Running in the morning is my hobby.
7. My sister and i have different interest.