Plastics are materials which are softened by heat and set into lasting form when shaped in a mold. Some are natural; some are semi-synthetic , the result of chemical action on natural substance; some are synthetic, built up from the constituents of oil or coal. All are based on the chemistry of carbon, with its capacity for forming chains. The molecules that compose them link together in the setting or curing process to form chains , which give plastics their flexible strength. Some plastics retain their ability to be softened and reshaped; like wax, they are thermoplastic. Others set permanently in the shapes they are given by heat and pressure; like eggs, they are thermosetting. From industrial beginnings in the nineteenth century, plastics have struggled through a hundred and twenty years of glory, failure, disrepute and suspicion on the slow road to public acceptance. Now, at last, one can positively say that plastics are appreciated and enjoyed for what they are; that they make modern life richer, more comfortable and convenient, and also more fun. Plastics are warm materials, sympathetic to the human touch, and their transformation into things that come into contact with human beings is entirely appropriate. The fact that there are plastic antiques comes as a shock to most people. How can a material that seems so essentially twentieth century, and one that is so much associated with cheap, disposable products, has a history at all? It is a young technology, and a great part of the fun of collecting plastics is that beautiful pieces of historical interest can still be found very cheaply. 21. The word sympathetic in Paragraph 2 most probably means_______. A. harmful B. agreeable C. pitiful D. sorry 22. It can be concluded from this passage that_______. A. plastics are synthetic materials B. plastics won public acceptance 120 years agoC. plastics are very harmful in modern lifeD. plastics are cheap as antiques 23. Which of the following is essential to create any type of plastics? A. Carbon. B. Eggs. C. Oil. D. Coal. 24. Plastics that harden into permanent shapes are called_______. A. chained B. thermoplastic C. synthetic D. thermosetting 25. Which of the following is the best title for the passage? A. The Importance of Plastics in the Nineteenth Century. B. Why People Are Suspicious of Plastics. C. The Development of Plastics as a Modern Material. D. How Plastics Are Manufactured. 21. B 22. D 23. A 24. D 25. C
世界各地的人早餐一般吃什么?
老外聊天必备缩写,看你会多少?
无处可藏!科学家教你根据脸色来判断各种情绪
研究显示 精油会造成男性乳房发育症
About Love 关于爱
世界上最致命的动物 第一名居然不是人类
麦当劳在美国推出鲜肉汉堡
体坛英语资讯:New record set up for 7th Athens Half Marathon
缅甸总统吴廷觉辞职
国际英语资讯:Schools closed, flights canceled as fourth winter storm hits New York
国内英语资讯: Across China: Technology reshaping agriculture in China
国内英语资讯: Xi holds phone talk with Modi on bilateral ties
国际英语资讯:African countries sign agreement establishing continental free trade area
研究发现 微笑能给人造成压力也能缓解压力
十大手机厂商推“快应用”对抗小程序
国内英语资讯:Spotlight: Five years on, Xiplomacy is reshaping Chinas global role for a better world
体坛英语资讯:China starts training ahead of China Cup football tournament
中国药企热衷对美出口仿制药
白宫:川普不打算祝贺普京连任
体坛英语资讯:New weightlifting category introduced at Asian Games
儿科医生警告 过度使用触屏致儿童握笔难!
国内英语资讯:China urges efforts to ensure accomplishment of goals set in govt work report
Except, except for, apart from, besides 四种表示“除了”的说法
手机看多了眼睛累?七种办法帮你消除眼疲劳
英国王室出售哈里王子大婚纪念品 帮助流浪者
蕾哈娜手撕Snapchat,只因它做了这件事!
My Father 我的父亲
美剧《欲望都市》女演员或竞选州长
研究显示 气候变化对女性影响更大
成功人都有什么好习惯?
不限 |
英语教案 |
英语课件 |
英语试题 |
不限 |
不限 |
上册 |
下册 |
不限 |