下列山脉中属于第二阶梯和第三阶梯的分界线的是（    ）

    Ann is my classmate. She comes from New York, and she lives in Shanghai with her parents now. Every morning, she goes to KFC to have breakfast. Sometimes she buys a hamburger for me. She can't speak Chinese well. In the evening, her father often helps her with it. He's a teacher in our school. He can speak Chinese very well.

    Ann thinks the school life(生活)in China is very interesting. Ann likes reading Chinese books because she wants to know more about China. She tries(努力)to talk with her Chinese friends in Chinese. She hopes to speak Chinese well. She is very happy to live in China. She loves people here.

在购买灌装食品时，要注意看其生产日期及保质期，原因是超过保质期的食品其质量不能得到保证，根本原因是（    ）

根据短文理解, 从A、B、C三个选项中选择最佳答案填空。

    A thousand years ago, Hong Kong was covered by a  1 forest. As more and more people came to live in Hong Kong, these trees were 2 and burnt. Now there are only a few forests left and we call these 3, a small area covered with trees.

    Elephants, tigers and many 4 animals were living in the thick forest. Early farmers needed fire to keep themselves 5 in winter, to cook their food and to keep away the dangerous animals. They 6 rice and kept pigs and chickens in the valleys. They cut down the trees and burnt them. Elephants quickly disappeared 7 there was not enough food for them. So did most of the wolves and tigers. Monkeys and many other animals soon 8 in the same way.

    There are about 36 different animals living in Hong Kong now. One of the most interesting of Hong Kong's 9 is the barking deer. In Hong Kong the barking deer has only a real enemy human beings. There are now not 10 barking deer left. So it is important for people to protect wild animals.