With Airbus’ giant A380 airliner about to take to the skies, you might think planes could not get much bigger-and you would be r

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问题     With Airbus’ giant A380 airliner about to take to the skies, you might think planes could not get much bigger-and you would be right. For a given design, it turns (1)_____, there comes a point where the wings become too heavy to generate (2)_____ lift to carry their own weight. (3)_____ a new way of designing and making materials could (4)_____ that problem. Two engineers (5)_____ University College London have devised all innovative way to customize and control the (6)_____ of a material throughout its three-dimensional structure.
    In the (7)_____ of a wing, this would make possible a material that is dense, strong and load-bearing at one end, close to the fuselage, (8)_____ the extremities could be made less dense, lighter and more (9)_____. It is like making bespoke materials, (10)_____ you can customize the physical properties of every cubic millimeter of a structure.
    The new technique combines existing technologies in a(n) (11)_____ way, It starts by using finite-element-analysis software, of the type commonly used by engineers, (12)_____ a virtual prototype of the object. The software models the stresses and strains that the object will need to (13)_____ throughout its structure. Using this information it is then (14)_____ to calculate the precise forces acting on millions of smaller subsections of the structure. (15)_____ of these subsections is (16)_____ treated as a separate object with its own set of forces acting on it-and each subsection (17)_____ for a different microstructure to absorb those local forces.
    Designing so many microstructures manually (18)_____ be a huge task, so the researchers apply an optimization program, called a genetic algorithm, (19)_____. This uses a process of randomization and trial-and-error to search the vast number of possible microstructures to find the most (20)_____ design for each subsection.

选项 A、asks
B、calls
C、demands
D、requires

答案B

解析 考点为动词的搭配。call for需要;要求,如:to call for bid招标;The occasion calls for a cool head.这种场合需要冷静的头脑。其他选项:asks for请求;demands和requires为及物动词,与for不能搭配。
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