新概念英语问题Write questions and answers.用所给的词写出问句并回答.例句Whose/that

新概念英语问题
Write questions and answers.用所给的词写出问句并回答.
例句Whose/that black case?-Anna's Whose is that black case?-The case is Anna's.
我答的是
2 Whose/ the blue shirt?-my brother's __Whose is the blue shirt?The blue shirt is my brother's.
3 Whose/ this red pencil?- Steven's ____Whose is this red pencil?The red pencil is Steven's.
4 Whose/ that green tie?- my father's __Whose is that green tie?The green tie is my father's.
书上的答案是
2 Whose/ the blue shirt?-my brother's _Whose is the blue shirt?Theblue shirt is my brother's.
3 Whose/ this red pencil?- Steven's _Whose is this red pencil?The red pencil is Steven's.
/ that green tie?- my father's _Whose is that green tie?The green tie is my father's
请问应该填the还是that/this?
书中例句是the,而答案却不是,为什么?