【单选题】
{{B}}SectionA、{{/B}}
{{B}}Directions:{{/B}}Each of the passages is followed by some questions. For each question four answers are given. Read the passages carefully and choose the best answer to each question. Put your choice on theANSWER SHEET.
{{B}}Passage One{{/B}}
Bicycles for amateurs have up to now been made of steel, aluminum or magnesium tubes welded together into the conventional "A-frame" shape.But last year, theBritish competitorChrisBoardman set world records while winning titles in the Olympic cycling pursuit events on a custom-built, carbon-fibre bicycle with lower weight and wind resistance than standard models.Because carbon fibre is born light and extremely strong, it does not need theA-frame shape, saving further weightCarbon fibre can also be moulded in a single piece, avoiding the weakness of welds.
The new bike, which will cost between $ 2000 and $ 3000 when it reaches the shops next month, has the same advantages as the Olympic model, it weighs about 11 kilograms, a saving of 1.5 kilograms on metal frames With no crossbar, it has a lower centre of gravity, making it easier to use in race conditions. "When you’re doing some aggressive riding, you throw the bike about form side to side," explainsEddieEccleston, director ofBritishEagle, aBritish bicycle manufacturer based in Powys, Wales, which is marketing the bikes. "The low centre of gravity! gives you better control."
The frames are being made in the US forBritishEagle by SP systems inCamarillo,California, which has clients in the aerospace industry. "This is aerospace technology brought into cycling by enthusiasts," saysEccleston. When professionals tested racing versions of the bike before the Tour de France, they were quicker than metal versions by up to 3 seconds per kilometre.
The new design has no struts between the saddle and the back wheel; instead, the frame’s flexibility can be "tuned" to individual tastes by changing the mixture of Kevlar fibre and carbon fibre in the back wheel strut, allowing up to 5 centimetres of movement.
The carbon-fibre design has a lower centre of gravity and smoother back-wheel suspension than conventional bikes.
B．it was the first commercial mountain bike
C．its public showing last weekend aroused many people’s curiosity
D．it was made of one single piece of carbon fibre
网考网参考答案：D
网考网解析：
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