首页
登录
职称英语
For centuries men dreamed of achieving vertical flight. In 400 A.D. Chinese
For centuries men dreamed of achieving vertical flight. In 400 A.D. Chinese
游客
2023-08-21
55
管理
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 con ceive the first mechanical【B1】______,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 look ing craft of steel tubing with a rotating fan【B2】______.It rose awkwardly and verti cally into the air from a standing start,hovered a few feet above the ground,went【B3】______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. Peo ple anticipated that vertical flight transports would carry millions of passengers as do the airliners of today. Such fantastic expectations were not【B4】______.
The helicopter has now become an extremely useful machine. It【B5】______in military missions, carrying troops, guns and【B6】______ instruments where other air craft cannot go. Corporations use them as airborne offices, many metropolitan areas use them in po lice work, construction and logging companies employ them in various【B7】______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【B8】______crews and supplies. Any urgent mission toa hard-to-get-to placeisa likely task for a helicopter.Among their other【B9】______of use:deliver people across town,fly to and from airports,【B10】______ rescue work, and aid in the search for missing or wanted persons. [br] 【B4】
选项
答案
fulfilled
解析
fulfill意为“实现”,与were构成被动语态,因而空格处要填入过去分词形式fulfilled。
转载请注明原文地址:http://tihaiku.com/zcyy/2945781.html
相关试题推荐
Forcenturies,farmershaveusedwindmillstopumpwater,crushgrainandpe
Forcenturies,farmershaveusedwindmillstopumpwater,crushgrainandpe
Forcenturies,farmershaveusedwindmillstopumpwater,crushgrainandpe
Forcenturies,farmershaveusedwindmillstopumpwater,crushgrainandpe
Forcenturies,farmershaveusedwindmillstopumpwater,crushgrainandpe
Forcenturies,farmershaveusedwindmillstopumpwater,crushgrainandpe
Forcenturies,farmershaveusedwindmillstopumpwater,crushgrainandpe
Forcenturies,farmershaveusedwindmillstopumpwater,crushgrainandpe
Forcenturies,farmershaveusedwindmillstopumpwater,crushgrainandpe
Forcenturies,farmershaveusedwindmillstopumpwater,crushgrainandpe
随机试题
FamilyMattersThismonth,Wyomingpassedabilltha
Withitsrecession-friendlycoffeeprices,plentifultablesandavailablebat
Thelastfiveyearshaveseena(n)______improvementinthecountry’seconomy.A
Peopleintheirsixtiesshouldgotouniversitytoretrainbecausethey
WhatisthemostimportantfactorforarockettoescapefromtheEarth?[br]Wh
在Linux中,创建权限设置为-rw-rw-r--的普通文件,下面的说法中正确
某运输公司需要购买卡车10辆,有两种方案可供选择,用费用现值法进行方案必选。现金
患者男,6岁。突起高热入院,查体:精神萎靡,面色青灰,四肢厥冷,反复抽搐。T40
下列缺陷中,属于一般缺陷的有()。(A)SF6断路器弹簧机构操作机构机构箱密封不
患者男,65岁。慢性咳嗽、咳痰30年,双下肢水肿5年。查体:颈静脉怒张,口唇发绀
最新回复
(
0
)