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     My name is Chen Yang. I'm twelve years old. I'm a Chinese student.

     There are four people in my family—my father, my moth er, my brother and I. My father is a doctor at the City Central Hospital and my mother is a theatre manager. My brother is a student, too. He is thirteen. We are in the same school, but not in the same class.

I like English very much. I can speak a lot of English. I want to have an American pen friend. Let's be friends, OK? Please write to me. My address is No. 22 Middle Sc hool, Hunan, China. My email is Cheny @ hotmail. com.

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“它拓展了人类活动的范围，海洋在人类文明中的地位迅速上升，世界的人种地理分布、宗教与文化格局开始发生重大变化。”造成这种重大影响的历史事件是（    ）