A:NH4HCO3溶液中加入过量稀NaOH溶液 NH4++ OH-=NH3·H2O
B:FeBr2溶液中通入足量的氯气:2Fe2++2Br-+2Cl2=2Fe3++Br2+4Cl-
C:硫酸亚铁溶液中加入用硫酸酸化的双氧水:Fe2++2H++H2O2=Fe3++2H2O
D:在通入过量SO2后的NaOH溶液中加足量的溴水(不考虑SO2的溶解):
要想了解中世纪阿拉伯世界的有关历史,可以参阅下列哪部书籍( )
图7是基于粤、苏、贵、桂四省区1990年的省际人口迁移、自然增长率、老年人口数量、经济发展水平,预测的2050年这四个省区老年人口比重的变化。读图完成各题。
阅读理解
Alan and Cindy are in the same school. There are many school rules here. First, they can’t listen to music in the classroom or hallways. But they can listen to it outside or in the music room. Second, they can’t eat in the classroom but they can eat in the dining hall. Can they wear hats in class? No, they can’t. What other(其他的)rules do they have? They can't fight with their(他们的)classmates, either. Fights can make the teachers really unhappy…
根据短文内容,完成表格
can
can’t
listen to music
1_____________________
2_____________________
3_____________________
4_____________________
5_____________________