共用题干 The World's Longest BridgeRumor has it that a legendary six-headed monster lurks in the deep wa...

共用题干
The World's Longest Bridge

Rumor has it that a legendary six-headed monster lurks in the deep waters of the Tyrrhenian Sea between Italy and the island of Sicily._______(46)When completed in 2010,the world's longest bridge will weigh nearly 300,000 tons一equivalent to the iceberg that sank the Titanic一and stretch 5 kilometers long."That's nearly 50 percent longer than any other bridge ever built."says structural engineer Shane Rixon.
_______(47)They're suspension bridges,massive structures built to span vast water channels or gorges.A suspension bridge needs just two towers to shoulder the structure's mammoth weight, thanks to hefty supporting cables slung between the towers and anchored firmly in deep pools of cement at each end of the bridge.The Messina Strait Bridge will have two 54,100-ton towers,which will support most of the bridge's load.The beefy cables of the bridge,each 1.2 meter in diameter, will hold up the longest and widest bridge deck ever built.
When construction begins on the Messina Strait Bridge in 2005,the first job will be to erect two 370 meter-tall steel towers._______(48)Getting these cables up will be something. It's not just their length一totally 5.3 kilometers一but their weight._______(49)
After lowering vertical"suspender"cables from the main cables,builders will erect a 60- meter一wide 54,630一ton steel roadway,or deck一wide enough to accommodate 12 lanes of traffic.The deck's weight will pull down on the cables with a force of 70,500 tons.In return,the cables yank up against their firmly rooted anchors with a force of 139,000 tons一equivalent to the weight of about 100,000 cars. Those anchors are essential._______(50) _______（50）