题干

上年年初以来,双汇“瘦肉精”事件引起了社会的广泛关注。人在大量食用喂食“瘦肉精”的猪肉后会出现手脚发麻、心率加快、呕吐等症状。有一种“瘦肉精”学名叫盐酸克伦特罗,化学式是C12H18Cl2N2O。下列对于“瘦肉精”的认识不正确的是()

A:该物质是由碳、氢、氯、氮和氧五种元素组成的

B:每个盐酸克伦特罗分子中含有18个氢原子

C:盐酸克伦特罗分子中碳、氢两种元素的质量比为12∶18

D:盐酸克伦特罗的相对分子质量为277

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C

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Hi Brad,
    It's good to hear from you again. I find that I'm not good at writing compositions. It's hard for me to prepare the form of a composition and organize sentences. ①Could you tell me how to deal with this problem? I would really appreciate if you offer me some good methods.
Best wishes,
Cindy
Hi Cindy,
    A composition is really a story and any story is told to an audience. There is a form for this and it is in three parts. First, tell them(the audience) what you are going to tell them. Then tell them, and finally tell them what you told them. Parts one and three are short and most of the information is in part two. It works like this.
    Let's say you are asked to write a 200-word composition about your visit to the Great Wall. You would begin with an opening sentence or two saying something like “The Great Wall of China is a national ②landmark that is famous around the world. I visited it last summer and I want to tell you about it.” That uses about 25 words to tell them what you are going to tell them.
    The second part would be about 150 words and would contain information about the Great Wall such as how long it is, when it was built, who built it and why, the fact that it is one of the seven wonders of the world and you would talk about how you felt and what you thought when you visited this national treasure. This is telling them.
    Finally, you would use about another 25 words to say something like “That was my first visit to the Great Wall and it was a very emotional experience to actually touch something so old and famous.③每个中国人至少参观长城一次.I plan to go back whenever I can.” Here, you are telling them what you told them in the story and wrapping it all up into a neat package. This formula(惯例)works for both compositions and speeches and I think you will find it helps to organize your thoughts. I hope it's helpful.
Best wishes,
Brad Franklin