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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2024-03-11  10
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] 【C5】
选项
答案 I
解析 动词辨析题。空格所在句主语为the steel shells of hundreds of the ships，句中缺少谓语，因此空格处需要填入动词形式。此处叙述的是过去发生的事情，故该动词应用过去式。本段主要讲述的是二战期间，钢在低温下的易碎性首次成为主要问题，空格处所在句的后半句提到，12艘船裂成两半沉没，因此，此处是说数百艘船的钢壳在冰冷的北大西洋中裂开了。由此可以确定，动词I)cracked“(使)破裂，(使)裂开”为本题答案。备选的动词过去式中，besieged“包围，围攻，围困”、reshuffled“改组，进行岗位调整”和strived“努力；奋斗；抗争”均与此处意思不符，故排除。
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