首页
登录
职称英语
For centuries men dreamed of achieving vertical flight. In 400 AD Chinese ch
For centuries men dreamed of achieving vertical flight. In 400 AD Chinese ch
游客
2023-07-27
32
管理
问题
For centuries men dreamed of achieving vertical flight. In 400 AD Chinese children played with a fanlike toy that spun upwards and fell back to earth as rotation ceased. Leonardo da Vinci conceived the first mechanical apparatus, called a "Helix", which could carry a man straight up, but this was only a design and was never tested.
The ancient dream was finally realized in 1940 when a Russian engineer piloted a strange-looking craft of steel tubing with a rotating fan on top. It rose awkwardly and vertically into the air from a standing start, hovered a few feet above the ground, went sideways and backwards, and then settled back to earth. That vehicle was called a helicopter.
Imaginations were fired. Men dreamed of going to work in their own personal helicopters. People anticipated that vertical flight transports would carry millions of passengers as do the airlines of today. Such fantastic expectations were not fulfilled. The helicopter has now become an extremely useful machine. It excels in military missions, carrying troops, guns and strategic instruments where other aircraft cannot go. Corporations use them as airborne offices, many metropolitan areas use them in police work, construction and logging companies employ them in various advantageous ways, engineers use them for site selection and surveying, and oil companies use them as the best way to make offshore and remote work stations accessible to crews and supplies. Any urgent mission to a hard to-get-to place is a likely task for a helicopter. Among their other multitude of uses: deliver people across town, fly to and from airports, assist in rescue work, and aid in the search for missing or wanted persons. [br] When was the helicopter made?
选项
答案
The helicopter was made in 1940.
解析
第二段第一句话清楚地说明了人类最早实现飞的梦想是在1940年,一名俄国工程师成功发明第一架直升机。
转载请注明原文地址:https://tihaiku.com/zcyy/2873760.html
相关试题推荐
Believeitornot,anotherChineseathlete____________(又刷新了一项世界纪录)hassetupa
[originaltext]Mrs.RuthLi,aChinesewomanlivinginSingapore,namedher
TheMid-AutumnFestivalisatraditionalChinesefestivityand______(崇拜月亮的风俗可以
Centuriesago,mandiscoveredthatremovingmoisturefromfoodhelpstopres
Centuriesago,mandiscoveredthatremovingmoisturefromfoodhelpstopres
Centuriesago,mandiscoveredthatremovingmoisturefromfoodhelpstopres
Forcenturiesmendreamedofachievingverticalflight.In400ADChinesech
Forcenturiesmendreamedofachievingverticalflight.In400ADChinesech
Forcenturiesmendreamedofachievingverticalflight.In400ADChinesech
Centuriesago,duringtheMiddleAges,mostofthelandinEuropewasowned
随机试题
ItisacknowledgedthatthemodernmusicalshowisAmerica’smostoriginala
Againstabackgroundofgiantcolumnswithimagesofpyramidshungdozensof
根据下列材料,回答问1-20题 Theideathatplantsha
试比较胃大部切除术后频倒综合征与低d糖综合征发生机制的异同。
胖虎是学校初二年级的学生,老师发现他在学校里偷偷吸烟,经过班主任老师的教育,胖虎
在《旅游景区质量等级的划分与划定》中规定,旅游景区质量等级划分为五级,最高等级是
A.脾虚证 B.肾阳虚证 C.血热证 D.肾阴虚证 E.脾肾阳虚证右归丸
火的母行是A.木B.火C.土D.金E.水
公文筐测试也称为()。A.公文分类 B.公文整理 C.公文处理 D.公文归
下列关于法律所体现的意志的说法不正确的是A.法所体现的意志为社会各阶层的总体意志
最新回复
(
0
)