下列物质按混合物、氧化物、单质顺序进行分类的是( )
A:生理盐水、干冰、臭氧
B:石灰石、熟石灰、金刚石
C:冰水共存物、铁锈、氮气
D:空气、五氧化二磷、生铁
Last year, some groups of students in their community (社区) made a survey about "How do people spend their free time?" The following diagrams show some results of it:Diagram (1): Hours for people of different ages who surf the Internet in a week.Diagram (2): Different days people go to the library. (library attendance)Diagram (3): Different programs people like.根据上面三个图表内容,选择正确答案。
阅读下面一首诗,简析“心非木石岂无感”这个反问句在表现诗人情感变化过程中所起的作用。
《拟行路难》(其四)
泻水置平地,各自东西南北流。
人生亦有命,安能行叹复坐愁?
酌酒以自宽,举杯断绝歌路难。
心非木石岂无感?吞声踯躅不敢言。