题目

Do you know Australia? Australia is the largest island in the world．It is a little smaller than China．It is in the south of the earth． 1  The population of Australia is nearly as large as that of Shanghai．  2  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．  3  We had a wonderful time．Perth is famous for its beautiful wild flow下列物质中，遇到碘液变蓝的是（　　） A、蛋白质B、淀粉C、维生素D、二氧化碳