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.
1. The word sympathetic in Paragraph 2 most probably means_______.
A. harmful B. agreeable
C. pitiful D. sorry
2. It can be concluded from this passage that_______.
A. plastics are synthetic materials
B. plastics won public acceptance 120 years ago
C. plastics are very harmful in modern life
D. plastics are cheap as antiques
3. Which of the following is essential to create any type of plastics?
A. Carbon. B. Eggs.
C. Oil. D. Coal.
4. Plastics that harden into permanent shapes are called_______.
A. chained B. thermoplastic
C. synthetic D. thermosetting
5. 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.
1. B 2. D 3. A 4. D 5. C
2017届高考英语一轮复习课时知能训练:人教版必修四 Unit 1《Women of achievement》
2017届高考英语一轮复习课时知能训练:人教版必修五 Unit 5《First aid》
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2017版英语一轮精品复习学案:Unit1《Women of achievement》(新人教版必修4)
2017届高考英语一轮复习课时知能训练:人教版必修三 Unit 5《Canada—The True North》
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2017届高考英语一轮复习课时知能训练:人教版选修八 Unit 3《Inventors and inventions》
2017届高考英语一轮复习课时知能训练:人教版选修7 Unit 4《Sharing》
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2017届高考英语一轮复习课件人教版必修二 unit5《music》
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2017届高考英语一轮复习课时知能训练:人教版选修八 Unit 4《Pygmalion》
2017届高考英语一轮复习课时知能训练:人教版选修六 Unit 5《The power of nature》
2017届高考英语一轮复习课件人教版必修三 unit2《healthy eating》
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