1. (2022七上·和硕期末)  从方框中选择最佳选项完成对话。

A:Morning, Jack

B:It's a history book. 

A:

B:No,it isn't. It's my sister Mary's.

A:

B:She's eleven.

A:

B:Yes, it's her favorite subject.

A:. 

B: Because she thinks it's interesting.