根据短文理解, 完成下列各题。
Australia is the largest island in the world. It is a little smaller than China. It is in the south of the earth. Australia is big, but its population is small. The population of Australia is nearly as large as that of Shanghai.
Enough laws have been made to fight against pollution. The cities in Australia have got little air or water pollution. The sky is blue and the water is clean. You can clearly see fish swimming in the rivers. Plants grow very well.
Last month we visited Perth, the biggest city in Western Australia, and went to a wild flowers' exhibition (展览). There we saw a large number of wild flowers we had never seen before. We had a wonderful time. Perth is famous for its beautiful wild flowers. In spring, every year Perth has the wild flowers' exhibition. After visiting Perth, we spent a day in the countryside. We sat down and had a rest near a path at the foot of a hill. It was quiet and we enjoyed ourselves. Suddenly we heard bells ringing at the top of the hill. What we saw made us pick up all our things and run back to the car as quickly as we could. There were about three hundred sheep coming towards us down the path.
Australia is famous for its sheep and kangaroos. After a short drive from any town, you will find yourself in the middle of white sheep. Sheep, sheep, everywhere are sheep.