“人海茫茫，找不出没有任何差异的两个人。”这主要说明生命是地球上最宝贵的东西。（   ）

阅读短文, 选择正确答案。

     I am an English girl. My name is Kate Green. I am thirteen. I am at school now. Look! This is my school. It is Hongda School. I am in Class Eight. I am in Row Four. I am in Team Six. I am Number Five. At school I have a good friend. She is a girl, too. Her name is Ann. She isn’t at school today. I think she is at home. My teacher's name is Mr. Smith. He is a very good teacher. Today he wears (穿) a new T-shirt. He looks very young. I don't know his age. But I think he is old, because （因为）he has a son and a daughter. His son is a doctor and his daughter is a policewoman.