首页
外语
计算机
考研
公务员
职业资格
财经
工程
司法
医学
专升本
自考
实用职业技能
登录
专升本
For centuries men dreamed of achieving vertical flight. In 400 A. D. Chinese children played with a fan-like toy that spun upwar
For centuries men dreamed of achieving vertical flight. In 400 A. D. Chinese children played with a fan-like toy that spun upwar
admin
2014-06-25
44
问题
For centuries men dreamed of achieving vertical flight. In 400 A. D. Chinese children played with a fan-like toy that spun upwards and fell back to earth as rotation ceased. Leonardo da Vinci conceive the first mechanical apparatus, called a "Helix," which could carry man straight up, but 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. The vehicle was called a helicopter.
Imaginations were fired. Men dreamed of going to work in their own personal helicopters. People anticipate that vertical flight transports would carry millions of passengers as do the airliners 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.
What is said about the development of the helicopter?
选项
A、Helicopters have only been worked on by man since 1940.
B、Chinese children were the first to achieve flight in helicopters.
C、Helicopters were considered more dangerous than the early airplanes.
D、Some people thought they would become widely used by average individuals.
答案
D
解析
转载请注明原文地址:https://kaotiyun.com/show/HXUC777K
本试题收录于:
英语题库普高专升本分类
0
英语
普高专升本
相关试题推荐
Weaskedalocal______(art)tocomeandshowherworktothestudents.
Anowl(猫头鹰)isabird.Therearetwobasictypesofowls:typicalowlsandbarnowls.Owlsliveinalmosteverycountryofthew
(英语专业学生做)Ineverycultivatedlanguagetherearetwogreatclassesofwordswhich,takentogether,comprisethewholevocabu
(英语专业学生做)Ineverycultivatedlanguagetherearetwogreatclassesofwordswhich,takentogether,comprisethewholevocabu
Childrenwhoareoverprotectedbytheirparentsmaybecome______.
JohnhasjustleftNewYork,butIdidnotknowhe______untilyesterday.
DuringtheSecondWorldWarHitler______manycountries.
Byadoptingafewsimpletechniques,parentswhoreadtotheirchildrencangreatlyincreasetheirchildren’slanguagedevelopme
Anymistakemadeintheprintingofastampraisesitsvaluetostampcollectors.Amistakeononeinexpensivepostagestamphas
Thesuggestion______newrules______adoptedcamefromtheheadmaster.
随机试题
男婴,5个月。生后接种卡介苗后引起全身反应。近2~3个月来,感染不断,常患鹅口疮、上呼吸道感染及肠炎。各项免疫球蛋白测定均低,OT试验多次阴性。X线片示:胸腺影缺如。
可用于耐药金葡菌感染的半合成青霉素是
能恢复咀嚼功能的保护器是
A.散发B.暴发C.流行D.大流行E.感染短时期内突然出现很多病例,称为()
特殊染色见肾小球基底膜有钉状突起的肾小球肾炎是
某公司生产销售A、B、c三种产品,销售单价分别为20元、25元、10元;预计销售量分别为3000件、2000件、1500件;预计各产品的单位变动成本分别为12元、14元、8元;预计固定成本总额为245万元。按联合单位法(产品销量比为A:B:C=6:4:3)
根据我国《民法总则》的规定,()以上,可以独立实施民事法律行为,为完全民事行为能力人。
公安机关对人民检察院不批准逮捕的决定认为有错误的时候,可以()。
根据图表回答题。税收收入年增长速度居第三位的年份,比2003年增长了()亿元。
WhathappenstoDon?
最新回复
(
0
)