下列地理事件属于自然灾害的是（）

    Liu Mei has a h____ family. She lives w____ her grandparents and parents in Dantu. Her father is a doctor. He goes to work o____ foot every day. He is not very tall, b____ he is very strong. Her mother is a teacher. She goes to work by car. She often h____ her students at school. Liu Mei's grandparents stay at home. In the morning, they go t____ the park. In the afternoon, they d____ tea with their friends. In the e____, they watch TV .Liu Mei is a student in No.1Middle School. Her school is beautiful. There are many tall b____ there. She wants to s____ everyone around her school. She likes it very much.

北方地区中，各地共同的自然特征是（　　）