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
外语
Man has long wanted to fly. He saw birds, envied them and tried to imitate them. Over the ages, countless attempts were made: me
Man has long wanted to fly. He saw birds, envied them and tried to imitate them. Over the ages, countless attempts were made: me
admin
2008-11-28
67
问题
Man has long wanted to fly. He saw birds, envied them and tried to imitate them. Over the ages, countless attempts were made: men constructed wings, fastened them to their arms and legs and jumped off towers and hilltops. These "bird-men" flapped (拍动) their wings for a short space of time and then fell to the ground.
【B1】
What was not realized in those early years was that birds have muscles very much stronger, in proportion to their size, than men
. Human limbs cannot provide sufficient strength to lift the body off the ground.【B2】
The secret of flight did not lie in the making of wings, but in discovering the right kind of power, and how to use it.
In the 18th century, the invention of the hot-air balloon by the Montgolfier brothers of France was seen as a great step forward,【B3】
But balloons and the cigar-shaped airship, which was invented slightly later, did not solve the problem of flying because they had no means of power or control.
So the difficulty remained: a true flying machine which was heavier than air and capable of carrying people was still to be invented.【B4】
Experiments were carried out in many countries, sometimes with models driven by steam engines, but these were too heavy to be used in an airplane with a pilot.
The answer finally came at the beginning of this century with the invention of the internal combustion engine (内燃机)--the kind used in motor cars. Here at last was a powerful, yet comparatively light engine, driven by petrol and capable of being fitted into an airplane.
In 1903, two Americans, the brothers Wilbur and Orville Wright, flew a powered airplane for the first time. Their success encouraged designers everywhere.【B5】
Although there were now newer, different problems, mainly to do with safety and the training of pilots, progress was rapid.
These were exciting days and interest was intense. The age of airplane arrived.
Experiments were carried out in many countries, sometimes with models driven by steam engines, but these were too heavy to be used in an airplane with a pilot.
选项
答案
许多国家做了实验,有时用的是蒸汽机驱动的模型,但是这些模型对于由一个飞行员操作的飞机来说都太重。
解析
转载请注明原文地址:https://kaotiyun.com/show/2lfK777K
本试题收录于:
浙江省大学英语三级题库大学英语三级分类
0
浙江省大学英语三级
大学英语三级
相关试题推荐
ManagingMoneyImportantTips;1.Watchhowmuchyouspend—Don’toverspend,e.g.ifyouearn$2000,don’tspend$2500.—Cutb
Whydoestheglobalfundstopsupportinganynewprogrammes?
Readingortheenjoymentofbookshasalwaysbeenregardedamongthecharmsofaculturedlifeandisrespectedandenviedbyth
PierreOmidyar,thesonofFrench-Iranianimmigrants,wasalreadyamillionairebeforehelaunchedeBay.Omidyar’selectronicss
Inthepast,huntingwasanecessity,withhumanskillingwildanimalsforfoodandclothing.However,modernhuntersgenerally
London,England—VirtuallyeverycountryinEuropeisinanimmigrationmess.Governmentsaretryingtobalancetheconcernsoft
Mr.Smithisbookingatourforaladyandhimselfatatravelagency.
Musicmeansdifferentthingstodifferentpeopleandsometimesevendifferentthingstothesamepersonatdifferentmomentsof
JanetJacksontoldtheaudienceattheBlackEntertainmentTelevisionAwardsthattheentireJacksonfamilyhadwantedtoattend
JanetJacksontoldtheaudienceattheBlackEntertainmentTelevisionAwardsthattheentireJacksonfamilyhadwantedtoattend
随机试题
台湾与大陆和平统一后,台湾特别行政区可以享有比香港、澳门特别行政区更高度的自治权利,主要体现在()
男性,35岁,头痛、头晕1年,加重1周伴心悸、乏力、鼻出血及牙龈出血。查体:血压170/110mmHg,皮肤黏膜苍白,Hb65g/L,PLT148×109/L,尿蛋白(+++),尿红细胞3~5个/HP,BUN38mmol/L,Scr887μmo
下列各项中,除哪项外,均是肾病综合征的临床表现()
下列各项中,属于业务单位战略的有()。
以下不属于双轨学制的代表国家有()。
关于公民民事权利能力的表述,正确的是()。
Themarathonaimsto
Workisoneofsociety’smostimportantinstitutions.Itisthemainmechanismthroughwhichspendpowerisallocated.Itprovid
Myfirst(impress)______ofEnglandwasthatitwasagreyandrainyplace.
Automakersaredoingallsortsofthingstocarstomakethemsmarterandmoreautonomous,asregularreadersareaware.Here’s
最新回复
(
0
)