Rescue Platform In the aftermath of the terrorist attacks on the World Trade Center, security experts are trying to develop new ways of rescuing people from burning skyscrapers. One _____（51） is a platform capable of flying vertically and hovering in the air _____ （52）a helicopter. The platform would rise up and down alongside a skyscraper and pick up people _____（53）in high stories. The idea for vertical takeoff platform was hatched（策划）more than ten years ago by a Russian aerospace engineer, David Metreveli, who has since moved to Israel. Metreveli’s design _____（54）the Eagle, calls for two jet engines that_____（55） four large horizontal propellers. The spinning of the propellers _____（56） the necessary lift, or upward force, to raise the platform. The more _____（57） is supplied to the propellers, the higher the platform_____（58）. Moving the platform sideways involves_____（59）differing amounts of power to each propeller. Helicopters are now used in some_____（60） to get people out of burning building. Escape baskets slung from them dangle beside the building for people to climb into._____ （61）, the baskets cannot reach every floor of a building_____（62） the ropes from which they hang become unstable_____（63） a certain length. So far, Metreveli has built a small-scale model of the Eagle to_____（64） his idea. In the wake of September 11, he has been able to secure enough funding to start building a larger, 4-meter by 4-meter prototype, _____（65） he calls the Eaglet.

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