重点词汇： 表示家庭成员：sister, brother, father, mother, parents, grandparent, aunt, uncle, son, daughter, cousin
指示代词： these，those
人称代词： he，she
其他重要单词： friend, picture, dear, for, photo, here, are
重点短语：thanks for, family tree, a photo of
重点句型：
1. This / That is ...
2. These are / Those are ...
3. —Is this / that ...?
