Australia is a nation of immigrants because the overwhelming majority of the Australian population are ______.
A、white
B、middle class people
C、tourists from other countries
D、immigrants or their descendants
【正确答案】：D
【题目解析】：澳大利亚是一个移民国家，因为澳大利亚人口的绝大多数是移民或他们的后代。
