题目

下列各组中，酸与其酸酐对应错误的是……（ ）A、HPO3和P2O5     B、H3BO3和B2O3     C、HClO和Cl2O     D、HNO2和NO2 答案：D 解析:含氧酸的酸酐是指含氧酸发生失水反应所得到的化合物，这个过程中不发生氧化还原反应，所有元素的化合价都不发生变化，据此可判断HNO2的酸酐为N2O3。无氧酸的酸酐通常是酸性氧化物，如CO2、SO2、SO3、SiO2、P2O5等(酸酐不一定能与水反应生成相应的酸，如SiO2)，但有机酸的酸酐不一定是酸性氧化The Internet has opened up a whole new online world for us to meet, chat and go where we’ve never been before.But just as in face to face communication, there are some rules of behavior that should be followed when on line. 1. Imagine how you’d feel if you were in the other person’s shoes.For anything you’re about to send: ask yourself, “Would I say this to the person’s face?” if the answer is no, rewrite and reread. 2.If someone in the chat room is rude to you, your instinct （本能）is to fire back in the same manner. But try not to do so. 3. If it was caused by a disagreement with another member, try to fix the situation by politely discussing it. Remember to respect the beliefs and opinions of others in the chat room.4. Offer advice when asked by newcomers, as they may not be sure what to do or how to communicate. When someone makes a mistake, whether it’s a stupid question or an unnecessarily long answer, be kind about it. If it’s a small mistake, you may not need to say anything. Even if you feel strongly about it, think twice before saying anything. Having good manners yourself doesn’t give you license to correct everyone else. 5. At the same time, if you find you are wrong, be sure to correct yourself and apologize to those that you have offended.It is not polite to ask others personal questions such as their age, sex and marital status. Unless you know the person very well, and you are both comfortable with sharing personal information, don’t ask such questions.A. It’s natural that there some people who speak rudely or make mistakes online.B. Repeat the process till you feel sure that you’d feel comfortable saying the words to the person’s face.C. Everyone was new to the network once.D. The basic rule is simple: treat others in the same way you would want to be treated.E. When you send short messages to a person online, you must say something beautiful to hear.F. You should either ignore the person, or use your chat software to block their messages.G. If you do decide to tell someone about a mistake, point it out politely.