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.