怎样写网络小说,风凌天下

當前位置：

2014年職稱英語考試試題衛(wèi)生類c級閱讀判斷強化練習(xí)題7

發(fā)表時間：2014/2/27 10:30:27 來源：互聯(lián)網(wǎng) 點擊關(guān)注微信：

【導(dǎo)讀】本文是由中大職稱英語考試網(wǎng)編輯整理的職稱英語衛(wèi)生類相關(guān)復(fù)習(xí)題，更多免費精選職稱英語考試練習(xí)題盡在中大職稱英語考試網(wǎng)，敬請關(guān)注！

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 idea is a platform capable of flying vertically and hovering in the air like a helicopter. The platform would rise up and down alongside a skyscraper and pick up people trapped in high stories.

The idea for the vertical takeoff platform was hatched more than ten years ago by a Russian aerospace engineer, David Metreveli, who has since moved to Israel. Metreveli's design, called the Eagle, calls for two jet engines that turn four large horizontal propellers. The spinning of the propellers generates the necessary lift, or upward force, to raise the platform. The more power is supplied to the propellers, the higher the platform rises. Moving the platform sideways involves applying differing amounts of power to each propeller.

Helicopters are now used in some cases to get people out of burning buildings. Escape baskets slung from them dangle beside the building for people to climb into. Unfortunately, the baskets cannot reach every floor of a building because the ropes from which they hang become unstable beyond a certain length.

So far, Metreveli has built a small-scale model of the Eagle to test 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, which he calls the Eaglet.

1). A rescue platform called the Eagle is capable of moving vertically but not sideways.