【实验原理】2KMnO4+5H2C2O4+3H2SO4═K2SO4+2MnSO4+10CO2↑+8H2O
【实验内容及记录】
实验编号
室温下,试管中所加试剂及其用量/mL
室温下溶液颜色褪至无色所需时间/min
0.6 mol/L
H2C2O4溶液
H2O
0.2 mol/L KMnO4溶液
3 mol/L
稀硫酸
1
3.0
2.0
4.0
2
5.2
3
1.0
6.4
请回答:
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。
有人说,中国存在着一种最古老的商朝的书面语.这里的“书面语”是指( )