阅读下面短文，从每题所给的A、B、C、D四个选项中选出能正确回答所提问题或完成所给句子的最佳答案。
Britain was once covered by thick forests,
home to many animals which no longer live here. There were wolves, bears and
wild cattle with less than four million people. They lived in small villages
protected by wooden walls from the animals outside.
However, all this changed. Now Britain's population has increased to 65 million. Three-quarters of
Britain consists of fields, towns or cities. Although 25% of land is
countryside, new methods of farming mean that there are fewer birds and small
animals than ever before. Britain is one of the few countries in the world
without a large wild carnivore(食肉动物).
Some people want to change this. Some say
that Britain needs to become more natural again and suggest trees and plants
that once grew in Britain should be allowed to grow again. They even say that
large wild animals which have not lived in Britain should be helped to return
and live wild. They call this "rewilding".
Not everyone agrees. In the last twenty
years, over one million trees have been planted and there are plans for more—but wild animals? Some people ask if wolves will
attack sheep or even humans. They are also angry that rewilding might mean an
end to walking in the hills many people enjoy. So far, there are no wolves or
bears in Britain's
forests—but soon there might be!
