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
寒假生活 My Life in Winter Holiday
日记荒谬的一天 Diary—An Absurd Day
读书的方法 Approaches to Reading
性格Personality
友情Friendship
关于网购的看法My View on Shopping Online
做一个乐观的人To Be an Optimistic Person
关于出国留学的调查A Survey on Study Abroad
谈军训 On Military Training
我们学校的运动会Our School Sports Meeting
No Breakfast No Good 不吃早餐不好
幸运号码真的能带来好运吗?Do Lucky Numbers Really Bring Good Luck?
学习知识要讲究方法 Approaches to Knowledge
英语角The English Corner
我的选择 My Choice
发改委再次上调成品油价,价格,上涨China raises fuel prices
习惯 Habits
英语的重要性 The Importance of English
一封售后服务邮件 An E-mail of After-sales Service
兴趣是最好的老师Interest Is the Best Teacher
礼貌用语的魔力Magic Power of Polite Words
旅行计划 Plan for Two Days in Beijing
邀请信 An Invitation
远离香烟 Give up Smoking
食品安全问题Food Safety Issues
道路安全 Road Safety
父爱Father Love
便条 Note
人物介绍 Introduce a Person
家的重要性The Importance of Family
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