题目

要除去铁粉中混有的少量铝粉，可选用下列试剂中的 (    ) A． 盐酸 B． 醋酸 C． 氢氧化钠溶液 D． 氨水 答案：C【详解】 铝和铁都能和盐酸、醋酸反应，都不能和氨水反应，铝可以与氢氧化钠溶液反应生成溶于水的偏铝酸钠，而铁不反应，所以可以用 NaOH溶液除去铁粉中混有的少量铝粉； 故答案为 C。阅读理解 　　There are many types of reports. A report is simply an account of something that has happened. The commonest are news reports. We get them in themselves, over radio and on television. Sometimes cinemas also show us newsreels. The main purpose of a newspaper is to provide news. If you examine a newspaper closely, you will find that there are all types of news: accidents, floods, fires, wars, fashions (服装), sports, books, etc. The news covers everything that happens to people and their surroundings. Sometimes there are news items which are very amusing. 　　A news report is usually very short, except when it is about something very important, but it contains (包含) a lot of information. It is also written in short paragraphs, the first paragraph is in fact a summary (总结) of the news item. It gives all the necessary information, what, when, where, how and why. The other paragraphs give full details of the subjects. There may also be interviews with people. The words actually spoken by them are within inverted commas (引号). Often there are photographs to go with the news to make it more interesting. (1)The easiest way to get today's news is ________. [　　] A．to go to the cinema B．to watch a color TV C．to read today's newspapers D．to listen to the music over radio (2)Newspapers sell well mainly because ________. [　　] A．they cost very little B．they are easy to get C．they have got pictures to go with the news D．they provide all sorts of news in them (3)If you want to get enough information about yesterday's traffic accident within a very short time, you'd better ________. [　　] A．read the first paragraph of the news report in today's newspaper B．start from the second paragraph of the news report in today's newspaper C．look through the whole news report in today's newspaper D．talk with people who have seen the accident (4)To interest more people, a news reporter ________. [　　] A．usually produces amusing news B．always writes very short news reports C．often prints pictures to go with the news D．sometimes provides long and important news (5)This passage mainly talks about ________. [　　] A．different types of reports B．news reports C．happenings to people and their surroundings D．the length of a news report