题目

已知臭氧能使湿润的KI淀粉试纸变蓝，反应的方程式为KI+O3+H2OKOH+I2+O2(未配平），下列说法正确的是（    ） A.O3在反应中被氧化成O2 B.1 mol O3在反应中只有 mol的氧原子化合价发生了变化 C.1 mol O3在反应中得到2 mol电子 D.反应中氧化产物与还原产物的物质的量之比为2∶3 答案：C 解析:由反应方程式可知，1 mol O3在反应中只有mol O3(即1 mol O)化合价发生了变化，得到2 mol电子。In a 2005 survey of 2,500 schoolchildren in six cities, including Beijing and Shanghai, it was found that about 77% of them were short of sleep. Should school hours be cut? In a new survey taken by the China Daily website, almost 70% of the 1,133 people online agreed with cutting school hours, while 22% disagreed and 10% gave no answer. Liu Xing (12-year-old, 6-grade student): I get up at 5:50 every school day, have breakfast at 6:15, leave home at 6:30 and, after a 30-minute bus ride, arrive at school at 7:00, a full hour before lessons start. Besides, I spend my weekends taking classes in math and English, as well as learning to play the piano. Wang Qun (Liu Xing’s mother): My son is still not doing enough to win a place at a top high school, as it is so competitive (竞争的). They want students with good English and math and also special skills. “Craig” (netizen (网民)): The best way for children to learn is through play. Through play, they can develop their characters, learn to be independent (独立的) and improve all kinds of skills. “Skylark” (netizen): Young parents have little time to play with their children, so letting them go home early is not a good idea. I think schools should have more activities for children after class. Qi Zhen (high school teacher): People might take some time to accept shorter school hours. It will also take time to change people’s traditional mind that going to college is the only way to a good job. 1. The China Daily website took a new survey to ________. A. see how many schoolchildren are short of sleep B. see what people think of cutting school hours C. give schoolchildren more time to play D. help Liu Xing with his math and English study 2. ________probably disagree with shorter school hours. A. Wang Qun and “Skylark”                  B. Liu Xing and “Craig” C. Liu Xing and “Skylark”                 D. “Craig” and Qi Zhen 3. When do Liu Xing’s school lessons start?   A. At 7:00.                              B. At 7:30. C. At 8:00.                              D. We don’t know. 4. Which is NOT true about Wang Qun? A. She wants her son to have many kinds of skills. B. She has little time to play with her son every day. C. She believes a happy childhood means a failed adulthood (成年). D. She’s quite sure her son will be able to get into a top high school. 5. What can we learn from Qi Zhen’s words?   A. Schools should have more activities for children after class.   B. All the schools will take shorter school hours soon.   C. There’ll be a long way to go to change people’s traditional mind.   D. Through play children can develop well in different ways.