题目

己知在碱性溶液中可发生如下反应：2R(OH)3 + 3C1O－+ 4OH－ = 2RO4n-+3Cl－ +5H2O。关于该反应的说法正确的是(     ) A．RO4n-中 R 的化合价是+6           B．ClO－是还原剂 C．由上述离子方程式可知，该反应是由氨水提供的碱性环境 D．反应过程中生成1mol RO4n-，转移6mol e-。 答案：AThere is a growing debate about the most effective way for students to study． Traditionally studying alone was thought to be the best way to ensure good exam results．When studying alone you can focus your mind better than when you are with others．You also have the freedom to choose what topic to study and when, as you don't need file agreement of others．Students that prefer to study alone often say that when they study with their classmates they waste a lot of time because the discussion is often about non-study topics such as television or holidays．In the last few years, however, more and more students have started studying in groups．There are several reasons many students prefer this method．First, they find that studying is more fun as they can share the experience with others rather than staying in their rooms． In groups, they can discuss the subject together and when something is not understood they can ask each other questions．They can use the knowledge of their classmates to help improve their own knowledge． Finally by discussing the topic they are able to both understand and remember it better．[写作内容] 请以约30个词概括上述短文的主要内容________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________