The opinion of many engineers is that the architects that designed tine New

游客2023-07-17 22

问题 The opinion of many engineers is that the architects that designed tine New York World Trade Center Twin Towers did a good job in designing the buildings. The buildings were safe from the hazards envisioned at the time. Indeed, they were designed to withstand the force of aircraft that might crash into them. They were not, however, designed to withstand the effects of the very high temperatures generated by the ignition of tons of aviation fuel carried by the aircraft.
Steel lightly covered with concrete is the main structural component of the towers and steel loses a lot of structural strength when heated to 1,100 degrees Centigrade and beyond, as it was. To shield the steel the towers beams(柱梁) were c0ated with a few centimeters of concrete. That insulation was to provide structural integrity for at least 1 hour of fire. The towers met that test. The south tower lasted 62 minutes. The north, 103 minutes. Tragedy followed when not all could escape prior to the collapse.
Most experts agree that the Twin Towers were very. well designed. Many also agree that the pan pie planning the attacks were very knowledgeable and aimed the aircraft at a height that would effect the most damage. The aircraft crash and the resulting fuel fed fires were aimed at about the 90th floor. That was just high enough to insure that the upper floors would weaken with the heat and crack down, dropping into the remaining part of the building. The mass of the falling top floors created such a falling load that some experts estimate it exceeded by 5 to 10 times normal bearing loads. The effect was like a giant hammer, each floor contributing more weight to be born by the next floor down.
Were the Trade Towers well designed? Engineers say yes. But, the public refers to the belief that architects will never again design a tall building without considering the effects of terrorist attacks of all potential kinds. That not only includes the ability of the structure to withstand attack but the means to allow the buildings occupants(居住者) to escape in time to survive. [br] As we know from the 3rd paragraph, many people believe that ______.

选项 A、the attack was led by Bin Laden
B、those who directed the attack was better engineers than those who built the towers
C、those who directed the attack know quite a lot about the towers
D、the attack was made spontaneously

答案 C

解析第三段第二句Many also agree that the people planning the attacks were very knowledgeable and aimed the aircraft at a height that would effect the most damage.，意思是“许多人都认为策划袭击的人知识渊博，他们使飞机在一个能对大厦造成最大破坏的高度进行攻击。”由此可知，这些人对大厦的结构特点非常了解，与C)含义相符。B)具有一定的迷惑性，但原文并没有说策划飞机袭击的人是工程师，更没有将他们的水平与建造大厦的工程师们相比，故排除；A)、D)原文均未涉及，故排除。

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