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Tổng hợp đề thi thử tiếng anh thpt quốc gia (Đề số 20)

Trắc nghiệm tiếng anh Thi tốt nghiệp

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Ngày đăng: 24-10-2025

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Thời gian làm: 00:59:00

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Biên soạn tệp:

Trần Khánh Trâm Hường

Tổng câu hỏi:

49

Ngày tạo:

15-10-2025

Tổng điểm:

10 Điểm

Câu hỏi

Số điểm

Lời giải

  1. Câu 1

    Read the following passage and mark the letter A, B, C, or D on your answer sheet to indicate the correct answer to each of the questions from 35 to 42.

    Glass is a remarkable substance made from the simplest raw materials. It can be colored or colorless, monochrome or polychrome, transparent, translucent, or opaque. It is lightweight impermeable to liquids, readily cleaned and reused, durableyet fragile, and often very beautiful Glass can be decorated in multiple ways and its optical properties are exceptional. In all its myriad forms - as table ware, containers, in architecture and design - glass represents a major achievement in the history of technological developments.

    Since the Bronze Age about 3,000 B.C., glass has been used for making various kinds of objects. It was first made from a mixture of silica, line and an alkali such as soda or potash, and these remained the basic ingredients of glass until the development of lead glass in the seventeenth century. When heated, the mixture becomes soft and malleable and can be formed by various techniques into a vast array of shapes and sizes. The homogeneous mass thus formed by melting then cools to create glass, but in contrast to most materials formed in this way (metals, for instance), glass lacks the crystalline structure normally associated with solids, and instead retains the random molecular structure of a liquid. In effect, as molten glass cools, it progressively stiffens until rigid,but does so without setting up a network of interlocking crystals customarily associated with that process. This is why glass shatters so easily when dealt a blow. Why glass deteriorates over time, especially when exposedto moisture, and why glassware must be slowly reheated and uniformly cooled after manufacture to release internal stresses inducedby uneven cooling.

    Another unusual feature of glass is the manner in which its viscosity changes as itturns from a cold substance into a hot, ductile liquid. Unlike metals that flow or “freeze” at specific temperatures glass progressively softens as the temperature rises, going through varying stages of malleability until it flows like a thick syrup. Each stage of malleability allows the glass to be manipulated into various forms, by different techniques, and if suddenly cooled the object retains the shape achieved at that point. Glass is thus amenable to a greater number of heat-forming techniques than most other materials.

    The word “durable”in paragraph 1 is closest in meaning to _________.

    • A.

      lasting

    • B.

      delicate

    • C.

      heavy

    • D.

      plain

  2. Câu 2

    Mark the letter A, B, C, or D on your answer sheet to indicate the sentence that best combines each pair of sentences in the following questions.

    She buys a lot of new dresses every month. She always dresses shabbily.

    • A.

      However a lot of new dresses she buys every month, she always dresses shabbily. 

    • B.

      However many new dresses she buys every month, she always dresses shabbily. 

    • C.

      Many as new dresses she buys every month, she always dresses shabbily. 

    • D.

      She always dresses shabbily because she buys a lot of new dresses every month.

  3. Câu 3

    Read the following passage and mark the letter A, B, C, or D on your answer sheet to indicate the correct answer to each of the questions from 35 to 42.

    Glass is a remarkable substance made from the simplest raw materials. It can be colored or colorless, monochrome or polychrome, transparent, translucent, or opaque. It is lightweight impermeable to liquids, readily cleaned and reused, durableyet fragile, and often very beautiful Glass can be decorated in multiple ways and its optical properties are exceptional. In all its myriad forms - as table ware, containers, in architecture and design - glass represents a major achievement in the history of technological developments.

    Since the Bronze Age about 3,000 B.C., glass has been used for making various kinds of objects. It was first made from a mixture of silica, line and an alkali such as soda or potash, and these remained the basic ingredients of glass until the development of lead glass in the seventeenth century. When heated, the mixture becomes soft and malleable and can be formed by various techniques into a vast array of shapes and sizes. The homogeneous mass thus formed by melting then cools to create glass, but in contrast to most materials formed in this way (metals, for instance), glass lacks the crystalline structure normally associated with solids, and instead retains the random molecular structure of a liquid. In effect, as molten glass cools, it progressively stiffens until rigid,but does so without setting up a network of interlocking crystals customarily associated with that process. This is why glass shatters so easily when dealt a blow. Why glass deteriorates over time, especially when exposedto moisture, and why glassware must be slowly reheated and uniformly cooled after manufacture to release internal stresses inducedby uneven cooling.

    Another unusual feature of glass is the manner in which its viscosity changes as itturns from a cold substance into a hot, ductile liquid. Unlike metals that flow or “freeze” at specific temperatures glass progressively softens as the temperature rises, going through varying stages of malleability until it flows like a thick syrup. Each stage of malleability allows the glass to be manipulated into various forms, by different techniques, and if suddenly cooled the object retains the shape achieved at that point. Glass is thus amenable to a greater number of heat-forming techniques than most other materials.

    What must be done to release the internal stresses that build up in glass products during manufacture?

    • A.

      The glass must be reheated and evenly cooled.

    • B.

      The glass must be cooled quickly. 

    • C.

      The glass must be kept moist until cooled. 

    • D.

      The glass must be shaped to its desired form immediately

  4. Câu 4

    Read the following passage and mark the letter A, B, C, or D on your answer sheet to indicate the correct answer to each of the questions from 28 to 34.

    Esperanto is what is called a planned, or artificial, language. It was created more than a century ago by Polish eye doctor Ludwik Lazar Zamenhof. Zamenhof believed that a common language would help to alleviate some of the misunderstandings among cultures.

    In Zamenhof’s first attempt at a universal language, he tried to create a language that was as uncomplicated as possible. This first language included words such as ab, ac, ba, eb, be, and ce. This did not result in a workable language in that these monosyllabic words, though short, were not easy to understand or to retain.

    Next, Zamenhof tried a different way of constructing a simplified language. He made the words in his language sound like words that people already knew, but he simplified the grammar tremendously. One example of how he simplified the language can be seen in the suffixes: all nouns in this language end in o, as in the noun amiko, which means “friend”, and all adjectives end in -a, as in the adjective bela, which means “pretty”. Another example of the simplified language can be seen in the prefix mal-, which makes a word opposite in meaning; the word malamiko therefore means “enemy”, and the word malbela therefore means “ugly” in Zamenhof’s language.

    In 1887, Zamenhof wrote a description of this language and published it. He used a pen name, Dr. Esperanto, when signing the book. He selected the name Esperanto because this word means “a person who hopes” in his language. Esperanto clubs began popping upthroughout Europe, and by 1950, Esperanto had spread from Europe to America and Asia.

    In 1905, the First World Congress of Esperanto took place in France, with approximately 700 attendees from 20 different countries. Congresses were held annually for nine years, and 4,000 attendees were registered for the Tenth World Esperanto Congress scheduled for 1914, when World War I erupted and forced its cancellation.

    Esperanto has had its ups and downsin the period since World War I. Today, years after it was introduced, it is estimated that perhaps a quarter of a million people are fluent in it. This may seem like a large number, but it is really quite small when compared with the billion English speakers and billion Mandarin Chinese speakers in today’s world. Current advocates would like to see its use grow considerably and are taking steps to try to make this happen.

    It can be inferred from the passage that the Esperanto word malespera means _________.

    • A.

      hopelessness

    • B.

      hope

    • C.

      hopeful

    • D.

      hopeless

  5. Câu 5

    Mark the letter A, B, C, or D on your answer sheet to indicate the correct answer to each of the following questions.

    If we leave here now, we can drive half the distance before we stop _________lunch.

    • A.

      for having

    • B.

      having had

    • C.

      having

    • D.

      to have

  6. Câu 6

    Mark the letter A, B, C, or D on your answer sheet to indicate the underlined part that needs correction in each of the following questions.

    The proposal (A) has repealed after a (B) twenty-minutes discussion (C)a number of objections to its failure (D)to include our district.

    • A.

       has repealed

    • B.

       twenty-minutes

    • C.

       a number 

    • D.

       to include

  7. Câu 7

    Mark the letter A, B, C, or D on your answer sheet to indicate the underlined part that needs correction in each of the following questions.

    In the 1920s, Tulsa had a (A)higher number of (B)millionaire than any (C)other U.S. (D)city.

    • A.

       higher

    • B.

       millionaire

    • C.

       other 

    • D.

       city

  8. Câu 8

    Read the following passage and mark the letter A, B, C, or D on your answer sheet to indicate the correct answer to each of the questions from 35 to 42.

    Glass is a remarkable substance made from the simplest raw materials. It can be colored or colorless, monochrome or polychrome, transparent, translucent, or opaque. It is lightweight impermeable to liquids, readily cleaned and reused, durableyet fragile, and often very beautiful Glass can be decorated in multiple ways and its optical properties are exceptional. In all its myriad forms - as table ware, containers, in architecture and design - glass represents a major achievement in the history of technological developments.

    Since the Bronze Age about 3,000 B.C., glass has been used for making various kinds of objects. It was first made from a mixture of silica, line and an alkali such as soda or potash, and these remained the basic ingredients of glass until the development of lead glass in the seventeenth century. When heated, the mixture becomes soft and malleable and can be formed by various techniques into a vast array of shapes and sizes. The homogeneous mass thus formed by melting then cools to create glass, but in contrast to most materials formed in this way (metals, for instance), glass lacks the crystalline structure normally associated with solids, and instead retains the random molecular structure of a liquid. In effect, as molten glass cools, it progressively stiffens until rigid,but does so without setting up a network of interlocking crystals customarily associated with that process. This is why glass shatters so easily when dealt a blow. Why glass deteriorates over time, especially when exposedto moisture, and why glassware must be slowly reheated and uniformly cooled after manufacture to release internal stresses inducedby uneven cooling.

    Another unusual feature of glass is the manner in which its viscosity changes as itturns from a cold substance into a hot, ductile liquid. Unlike metals that flow or “freeze” at specific temperatures glass progressively softens as the temperature rises, going through varying stages of malleability until it flows like a thick syrup. Each stage of malleability allows the glass to be manipulated into various forms, by different techniques, and if suddenly cooled the object retains the shape achieved at that point. Glass is thus amenable to a greater number of heat-forming techniques than most other materials.

    According to the passage, why can glass be more easily shaped into specific forms than can metals

    • A.

      It resists breaking when heated 

    • B.

      It has better optical properties. 

    • C.

      It retains heat while its viscosity changes. 

    • D.

      It gradually becomes softer as its temperature rises.

  9. Câu 9

    Mark the letter A, B, C, or D on your answer sheet to indicate the sentence that best combines each pair of sentences in the following questions.

    He didn’t take his father’s advice. That’s why he is out of work.

    • A.

      If he had taken his father’s advice, he would not have been out of work. 

    • B.

      If he took his father’s advice, he would not be out of work. 

    • C.

      If he had taken his father’s advice, he would not be out of work. 

    • D.

      If he takes his father’s advice, he will not be out of work.

  10. Câu 10

    Mark the letter A, B, C, or D on your answer sheet to indicate the correct answer to each of the following questions.

    The book says that the revolution was _________off by the assassination of the president.

    • A.

      launched

    • B.

      cropped

    • C.

      triggered

    • D.

      prompted

  11. Câu 11

    Mark the letter A, B, C, or D on your answer sheet to indicate the word that differs from the other three in the position of primary stress in each of the following questions

    • A.

      uncertain

    • B.

      arrogant

    • C.

      familiar

    • D.

      impatient

  12. Câu 12

    Mark the letter A, B, C, or D on your answer sheet to indicate the word(s) OPPOSITE in meaning to the underlined word(s) in each of the following questions.

    Mary decided to remain celibateand devote her life to helping the homeless and orphans.

    • A.

      single

    • B.

      married

    • C.

      divorced

    • D.

      separated

  13. Câu 13

    Read the following passage and mark the letter A, B, C, or D on your answer sheet to indicate the correct answer to each of the questions from 35 to 42.

    Glass is a remarkable substance made from the simplest raw materials. It can be colored or colorless, monochrome or polychrome, transparent, translucent, or opaque. It is lightweight impermeable to liquids, readily cleaned and reused, durableyet fragile, and often very beautiful Glass can be decorated in multiple ways and its optical properties are exceptional. In all its myriad forms - as table ware, containers, in architecture and design - glass represents a major achievement in the history of technological developments.

    Since the Bronze Age about 3,000 B.C., glass has been used for making various kinds of objects. It was first made from a mixture of silica, line and an alkali such as soda or potash, and these remained the basic ingredients of glass until the development of lead glass in the seventeenth century. When heated, the mixture becomes soft and malleable and can be formed by various techniques into a vast array of shapes and sizes. The homogeneous mass thus formed by melting then cools to create glass, but in contrast to most materials formed in this way (metals, for instance), glass lacks the crystalline structure normally associated with solids, and instead retains the random molecular structure of a liquid. In effect, as molten glass cools, it progressively stiffens until rigid,but does so without setting up a network of interlocking crystals customarily associated with that process. This is why glass shatters so easily when dealt a blow. Why glass deteriorates over time, especially when exposedto moisture, and why glassware must be slowly reheated and uniformly cooled after manufacture to release internal stresses inducedby uneven cooling.

    Another unusual feature of glass is the manner in which its viscosity changes as itturns from a cold substance into a hot, ductile liquid. Unlike metals that flow or “freeze” at specific temperatures glass progressively softens as the temperature rises, going through varying stages of malleability until it flows like a thick syrup. Each stage of malleability allows the glass to be manipulated into various forms, by different techniques, and if suddenly cooled the object retains the shape achieved at that point. Glass is thus amenable to a greater number of heat-forming techniques than most other materials.

    The words “exposed to” in paragraph 2 most likely mean _________.

    • A.

      hardened by

    • B.

      chilled with

    • C.

      subjected to

    • D.

      deprived of

  14. Câu 14

    Mark the letter A, B, C, or D on your answer sheet to indicate the sentence that best completes each of the following exchanges.

    Ken and Laura are saying goodbye to each other after going to LOTTE Center. And they are going to have a date with each other later.

    Laura: “Well, it’s getting late. Maybe we could get together sometime.” - Ken: “_________

    • A.

      Nice to see back you.

    • B.

      Take it easy. 

    • C.

      Sounds good. I’ll give you a call.

    • D.

      Yes, I’ve enjoyed it.

  15. Câu 15

    Mark the letter A, B, C, or D on your answer sheet to indicate the sentence that is closest in meaning to each of the following questions.

    Bill’s English is much better than it was.

    • A.

      Bill speaks English better now than he did before. 

    • B.

      Bill has started to learn English but doesn’t speak it well 

    • C.

      Bill has always spoken good English. 

    • D.

      Bill’s English was much better than it is now.

  16. Câu 16

    Read the following passage and mark the letter A, B, C, or D on your answer sheet to indicate thecorrect word or phrase that best fits each of the numbered blanks from 23 to 27. Fill in the appropriate word in question 24

    What is meant by the term economic resources? In general, these are all the natural, man-made, and human resources that go into the production of goods and services. Economic resources canbe broken down into (23) _________ general categories: property resource - land and capital, andhuman resources - labor and entrepreneurial skills.

    What do economists mean (24) _________ land? Much more than the non-economist, landrefers to all the natural resources (25) _________are usable in the production process: arable land,forests, mineral and oil deposits, and so on. What about capital? Capital goods are all the man­made aids to producing, storing, transporting, and distributing goods and services. Capital goodsdiffer from consumer goods in that (26) _________ satisfy wants directly, while the former doso indirectly by facilitating the production of consumer goods. It should be noted that capital as defined here does not refer to money. Money, as such, produces nothing.

    The term labor refers to the physical and mental talents of humans used to produce goods and services (with the exception of a certain set of human talents, entrepreneurial skills, which will be considered separately because of their special significance). Thus the services of a factory workeror an office worker, a ballet dancer or an astronaut all fall (27) _________ the general headingof labor.

    • A.

      calling

    • B.

      with

    • C.

      using

    • D.

      by

  17. Câu 17

    Read the following passage and mark the letter A, B, C, or D on your answer sheet to indicate the correct answer to each of the questions from 35 to 42.

    Glass is a remarkable substance made from the simplest raw materials. It can be colored or colorless, monochrome or polychrome, transparent, translucent, or opaque. It is lightweight impermeable to liquids, readily cleaned and reused, durableyet fragile, and often very beautiful Glass can be decorated in multiple ways and its optical properties are exceptional. In all its myriad forms - as table ware, containers, in architecture and design - glass represents a major achievement in the history of technological developments.

    Since the Bronze Age about 3,000 B.C., glass has been used for making various kinds of objects. It was first made from a mixture of silica, line and an alkali such as soda or potash, and these remained the basic ingredients of glass until the development of lead glass in the seventeenth century. When heated, the mixture becomes soft and malleable and can be formed by various techniques into a vast array of shapes and sizes. The homogeneous mass thus formed by melting then cools to create glass, but in contrast to most materials formed in this way (metals, for instance), glass lacks the crystalline structure normally associated with solids, and instead retains the random molecular structure of a liquid. In effect, as molten glass cools, it progressively stiffens until rigid,but does so without setting up a network of interlocking crystals customarily associated with that process. This is why glass shatters so easily when dealt a blow. Why glass deteriorates over time, especially when exposedto moisture, and why glassware must be slowly reheated and uniformly cooled after manufacture to release internal stresses inducedby uneven cooling.

    Another unusual feature of glass is the manner in which its viscosity changes as itturns from a cold substance into a hot, ductile liquid. Unlike metals that flow or “freeze” at specific temperatures glass progressively softens as the temperature rises, going through varying stages of malleability until it flows like a thick syrup. Each stage of malleability allows the glass to be manipulated into various forms, by different techniques, and if suddenly cooled the object retains the shape achieved at that point. Glass is thus amenable to a greater number of heat-forming techniques than most other materials.

    The word “it” in paragraph 3 refers to _________.

    • A.

      feature

    • B.

      glass

    • C.

      manner

    • D.

      viscosity

  18. Câu 18

    Mark the letter A, B, C, or D on your answer sheet to indicate the word(s) CLOSEST in meaning to the underlined word(s) in each of the following questions.

    My husband has lost his job, so we’ll have to tighten our beltto avoid getting into debt.

    • A.

      earn money

    • B.

      spend money

    • C.

      sit still

    • D.

      economize

  19. Câu 19

    Mark the letter A, B, C, or D on your answer sheet to indicate the correct answer to each of the following questions.

    My brother and I will never get along. We’re _________.

    • A.

      cats and dogs

    • B.

      chalk and cheese 

    • C.

      salt and pepper

    • D.

      brick and mortar

  20. Câu 20

    Mark the letter A, B, C, or D on your answer sheet to indicate the correct answer to each of the following questions.

    We put his success _________his efforts.

    • A.

      up to

    • B.

      down to

    • C.

      off at

    • D.

      up with

  21. Câu 21

    Read the following passage and mark the letter A, B, C, or D on your answer sheet to indicate the correct answer to each of the questions from 35 to 42.

    Glass is a remarkable substance made from the simplest raw materials. It can be colored or colorless, monochrome or polychrome, transparent, translucent, or opaque. It is lightweight impermeable to liquids, readily cleaned and reused, durableyet fragile, and often very beautiful Glass can be decorated in multiple ways and its optical properties are exceptional. In all its myriad forms - as table ware, containers, in architecture and design - glass represents a major achievement in the history of technological developments.

    Since the Bronze Age about 3,000 B.C., glass has been used for making various kinds of objects. It was first made from a mixture of silica, line and an alkali such as soda or potash, and these remained the basic ingredients of glass until the development of lead glass in the seventeenth century. When heated, the mixture becomes soft and malleable and can be formed by various techniques into a vast array of shapes and sizes. The homogeneous mass thus formed by melting then cools to create glass, but in contrast to most materials formed in this way (metals, for instance), glass lacks the crystalline structure normally associated with solids, and instead retains the random molecular structure of a liquid. In effect, as molten glass cools, it progressively stiffens until rigid,but does so without setting up a network of interlocking crystals customarily associated with that process. This is why glass shatters so easily when dealt a blow. Why glass deteriorates over time, especially when exposedto moisture, and why glassware must be slowly reheated and uniformly cooled after manufacture to release internal stresses inducedby uneven cooling.

    Another unusual feature of glass is the manner in which its viscosity changes as itturns from a cold substance into a hot, ductile liquid. Unlike metals that flow or “freeze” at specific temperatures glass progressively softens as the temperature rises, going through varying stages of malleability until it flows like a thick syrup. Each stage of malleability allows the glass to be manipulated into various forms, by different techniques, and if suddenly cooled the object retains the shape achieved at that point. Glass is thus amenable to a greater number of heat-forming techniques than most other materials.

    Why does the author list the characteristics of glass in paragraph 1?

    • A.

      To demonstrate how glass evolved 

    • B.

      To show the versatility of glass 

    • C.

      To explain glassmaking technology 

    • D.

      To explain the purpose of each component of glass

  22. Câu 22

    Read the following passage and mark the letter A, B, C, or D on your answer sheet to indicate the correct answer to each of the questions from 28 to 34.

    Esperanto is what is called a planned, or artificial, language. It was created more than a century ago by Polish eye doctor Ludwik Lazar Zamenhof. Zamenhof believed that a common language would help to alleviate some of the misunderstandings among cultures.

    In Zamenhof’s first attempt at a universal language, he tried to create a language that was as uncomplicated as possible. This first language included words such as ab, ac, ba, eb, be, and ce. This did not result in a workable language in that these monosyllabic words, though short, were not easy to understand or to retain.

    Next, Zamenhof tried a different way of constructing a simplified language. He made the words in his language sound like words that people already knew, but he simplified the grammar tremendously. One example of how he simplified the language can be seen in the suffixes: all nouns in this language end in o, as in the noun amiko, which means “friend”, and all adjectives end in -a, as in the adjective bela, which means “pretty”. Another example of the simplified language can be seen in the prefix mal-, which makes a word opposite in meaning; the word malamiko therefore means “enemy”, and the word malbela therefore means “ugly” in Zamenhof’s language.

    In 1887, Zamenhof wrote a description of this language and published it. He used a pen name, Dr. Esperanto, when signing the book. He selected the name Esperanto because this word means “a person who hopes” in his language. Esperanto clubs began popping upthroughout Europe, and by 1950, Esperanto had spread from Europe to America and Asia.

    In 1905, the First World Congress of Esperanto took place in France, with approximately 700 attendees from 20 different countries. Congresses were held annually for nine years, and 4,000 attendees were registered for the Tenth World Esperanto Congress scheduled for 1914, when World War I erupted and forced its cancellation.

    Esperanto has had its ups and downsin the period since World War I. Today, years after it was introduced, it is estimated that perhaps a quarter of a million people are fluent in it. This may seem like a large number, but it is really quite small when compared with the billion English speakers and billion Mandarin Chinese speakers in today’s world. Current advocates would like to see its use grow considerably and are taking steps to try to make this happen.

    The expression “popping up” in paragraph 4 could best be replaced by _________.

    • A.

      leaping

    • B.

      hiding

    • C.

      shouting

    • D.

      opening

  23. Câu 23

    Mark the letter A, B, C, or D on your answer sheet to indicate the correct answer to each of the following questions.

    When the weather was very hot in summer, sales of bottles of water went _________the roof.

    • A.

      through

    • B.

      to

    • C.

      above

    • D.

      over

  24. Câu 24

    Mark the letter A, B, C, or D on your answer sheet to indicate the word that differs from the other three in the position of primary stress in each of the following questions

    • A.

      opponent

    • B.

      contractual

    • C.

      disappear

    • D.

      arrangement

  25. Câu 25

    Read the following passage and mark the letter A, B, C, or D on your answer sheet to indicate the correct answer to each of the questions from 35 to 42.

    Glass is a remarkable substance made from the simplest raw materials. It can be colored or colorless, monochrome or polychrome, transparent, translucent, or opaque. It is lightweight impermeable to liquids, readily cleaned and reused, durableyet fragile, and often very beautiful Glass can be decorated in multiple ways and its optical properties are exceptional. In all its myriad forms - as table ware, containers, in architecture and design - glass represents a major achievement in the history of technological developments.

    Since the Bronze Age about 3,000 B.C., glass has been used for making various kinds of objects. It was first made from a mixture of silica, line and an alkali such as soda or potash, and these remained the basic ingredients of glass until the development of lead glass in the seventeenth century. When heated, the mixture becomes soft and malleable and can be formed by various techniques into a vast array of shapes and sizes. The homogeneous mass thus formed by melting then cools to create glass, but in contrast to most materials formed in this way (metals, for instance), glass lacks the crystalline structure normally associated with solids, and instead retains the random molecular structure of a liquid. In effect, as molten glass cools, it progressively stiffens until rigid,but does so without setting up a network of interlocking crystals customarily associated with that process. This is why glass shatters so easily when dealt a blow. Why glass deteriorates over time, especially when exposedto moisture, and why glassware must be slowly reheated and uniformly cooled after manufacture to release internal stresses inducedby uneven cooling.

    Another unusual feature of glass is the manner in which its viscosity changes as itturns from a cold substance into a hot, ductile liquid. Unlike metals that flow or “freeze” at specific temperatures glass progressively softens as the temperature rises, going through varying stages of malleability until it flows like a thick syrup. Each stage of malleability allows the glass to be manipulated into various forms, by different techniques, and if suddenly cooled the object retains the shape achieved at that point. Glass is thus amenable to a greater number of heat-forming techniques than most other materials.

    What does the author imply about the raw materials used to make glass?

    • A.

      They were the same for centuries.

    • B.

      They are liquid.

    • C.

      They are transparent.

    • D.

      They are very heavy

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