我在网上多方帮你查了资料，有些本来就是英文，有些是中文的我翻译了，整合后是以下结果，一共6句，确保语法正确、英语地道：
Australia is a country comprising the mainland of the Australian continent, the island of Tasmania, and numerous smaller islands. It is the world's sixth-largest country by total area.
Australia is a developed country and one of the wealthiest in the world, with the world's 12th-largest economy. In 2018 Australia had the world's fifth-highest per capita income, Australia's military expenditure is the world's 13th-largest.
With the second-highest human development index globally, Australia ranks highly in many international comparisons of national performance. These rankings include quality of life, health, education, economic freedom, and the protection of civil liberties and political rights. Australia is a member of the United Nations, G20, Commonwealth of Nations, ANZUS, Organisation for Economic Co-operation and Development (OECD), World Trade Organization, Asia-Pacific Economic Cooperation, and the Pacific Islands Forum.
With beautiful sceneries as well as a pleasant natural and cultural environment, Australia attracts millions of tourists and a considerable number of immigrants each year.
如果有哪里不大明白的你可以告诉我，我给你解释。希望这些信息对你有帮助，满意的话记得要采纳满意答案哦 :-)。