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  3. Steel is valued for its reliability, but not when it gets cold. Most forms of

Steel is valued for its reliability, but not when it gets cold. Most forms of

游客2023-08-08  7
问题    Steel is valued for its reliability, but not when it gets cold. Most forms of steel【C1】______become brittle (脆的) at temperatures below about -25℃ unless they are mixed with other metals. Now, though, a novel type of steel has been developed that resists【C2】______at much lower temperatures, while retaining its strength and toughness—without the need for expensive【C3】______.
   Steel’s fragility at low temperatures first became a major concern during the Second World War. After German U-boats torpedoed (用鱼雷攻击) numerous British ships, a 2,700-strong fleet of cheap- and-cheerful "Liberty ships" was introduced to replace the lost vessels, providing a lifeline for the【C4】______British. But the steel shells of hundreds of the ships【C5】______in the icy north Atlantic, and 12 broke in half and sank.
   Brittleness remains a problem when building steel structures in cold conditions, such as oil rigs in the Arctic. So scientists have【C6】______to find a solution by mixing it with expensive metals such as nickel.
   Yuuji Kimura and colleagues in Japan tried a more physical【C7】______. Rather than adding other metals, they developed a complex mechanical process involving repeated heating and very severe mechanical deformation, known as tempforming.
   The resulting steel appears to achieve a combination of strength and toughness that is【C8】______to that of modern steels that are very rich in alloy content and, therefore, very expensive.
   Kimura’s team intends to use its tempformed steel to make ultra-high strength parts, such as bolts. They hope to reduce both the number of【C9】______needed in a construction job and their weight—by replacing solid supports with【C10】______tubes, for example. This could reduce the amount of steel needed to make everything from automobiles to buildings and bridges.
   A) abruptly I) cracked
   B) additives J) fractures
   C) approach K) hollow
   D) ardently L) relevant
   E) besieged M) reshuffled
   F) channel N) strived
   G) comparable O) violent
   H) components [br] 【C3】
选项
答案 B
解析 名词辨析题。空格前面是形容词expensive，因此，空格处应填入名词形式作形容词的中心语。上文提到，大多数钢在温度低于大约零下25℃时突然变脆，除非与其他金属混合，而现在，一种新型的钢已经被开发出来解决钢的断裂问题。下文第三段指出，科学家通过把钢与镍等贵金属混合来解决钢的低温易碎问题，第四段第二句提到，木村勇次及其同事在开发这种新型钢时，没有添加其他金属，而是开发了一个复杂的机械过程达到了钢的强度和韧性的结合。因此，此处是说，这种新型钢可以在更低的温度下抵抗断裂，同时保持其强度和韧性，然而并不需要添加昂贵的材料。由此可以确定名词B)additives“添加物，添加剂”为本题答案。备选的其他名词中，均与此处要表达的“添加物”意思不符，故可排除。
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