I am Mary. I have a happy family. This is a photo of my family in the living room. Look at . What are we doing? My brother is drawing a picture. Do you see my parents and my little brother? Look at . They are on a couch (长沙发). My little brother is crying. My mother is singing a song to . My father is sitting beside my mother and looking at . Do you see ? Yes. I am playing with my toy.

us them him him me

第一空，根据语境“看……，我们在做什么？”，这里需要一个指代“我们”的词，“us”符合语境，表示“看我们”。
第二空，前面提到“Do you see my parents and my little brother?”，这里需要一个指代“我的父母和小弟弟”的词，“them”可指代复数的人，所以填“them”。
第三空，“My mother is singing a song to...”，这里需要一个指代“我的小弟弟”的词，“him”可指代男性单数，所以填“him”。
第四空，“My father is sitting beside my mother and looking at...”，这里需要一个指代“我的母亲”的词，“her”可指代女性单数，所以填“her”。
第五空，“Do you see...? Yes. I am playing with my toy.”，这里需要一个指代“我”的词，“me”符合语境。
关于“them、him、us、her、me”和“they、he、we、she、I”的区别：
“them、him、us、her、me”是宾格形式，在句子中作宾语；“they、he、we、she、I”是主格形式，在句子中作主语。

a. Where is Jenny's family?
b. Jenny and Danny are watching TV. Where is Jenny sitting?
c. Who is reading newspapers?
d. What are Bob and Lynn doing?
e. Where's Li Ming? What's he doing now?