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
Until men invented ways of staying underwater for more than a few minutes, the wonders of the world below the surface of the sea
Until men invented ways of staying underwater for more than a few minutes, the wonders of the world below the surface of the sea
admin
2017-03-25
57
问题
Until men invented ways of staying underwater for more than a few minutes, the wonders of the world below the surface of the sea were almost unknown. The main problem, of course, lies in air. How could air be supplied to swimmers below the surface of the sea? Pictures made about 2,900 years ago in Asia show men swimming under the surface with air bags tied to their bodies. A pipe from the bag carried air into the swimmer’s mouth. But little progress was achieved in the invention of diving devices until about 1490, when the famous Italian painter, Leonardo da Vinci, designed a complete diving suit.
In 1680, an Italian professor invented a large air bag with a glass window to be worn over the diver’s head. To "clean" the air a breathing pipe went from the air bag, through another bag to remove moisture, and then again to the large air bag. The plan did not work, but it gave later inventors the idea of moving air around in diving devices.
In 1819, a German, Augustus Siebe, developed a way of forcing air into the head covering by a machine operated above the water. Finally, in 1837, he invented the "hard-hat suit" which was to be used for nearly a century. It had a metal covering for the head and an air pipe attached to a machine above the water. It also had small openings to remove unwanted air. But there were two dangers to the diver inside the "hard-hat suit". One was the sudden rise to the surface, caused by a too great supply of air. The other was the crushing of the body, caused by a sudden diving into deep water. The sudden rise to the surface could kill the diver; a sudden dive could force his body up into the helmet, which could also result in death.
Gradually the "hard-hat suit" was improved so that the diver could be given a constant supply of air. The diver could then move around under the ocean without worrying about the air supply.
During the 1940s diving underwater without a special suit became popular. Instead, divers used a breathing device and a small covering made of rubber and glass over parts of the face. To improve the swimmer’s speed another new invention was used: a piece of rubber shaped like a giant foot, which was attached to each of the diver’s own feet. The manufacture of rubber breathing pipes made it possible for divers to float on the surface of the water, observing the marine life underneath them. A special rubber suit enabled them to stay in cold water for long periods, collecting specimens of animal and vegetable life that had never been obtained in the past.
The most important advance, however, was the invention of a self-contained underwater breathing apparatus, which is called a "scuba".
Invented by two Frenchmen, Jacques Cousteau and Emile Gagnan, the scuba consists of a mouthpiece joined to one or two tanks of compressed air which are attached to the diver’s back. The scuba makes it possible for a diver scientist to work 200 feet underwater or even deeper for several hours. As a result, scientists can now move around freely at great depths, learning about the wonders of the sea.
The main progress mentioned in this passage was______ .
选项
A、an Italian professor invented a large air bag
B、men invented the best diving devices
C、an Italian painter designed a complete diving suit
D、an air bag
答案
C
解析
根据文中第一段的“But little progress was achieved in the invention of diving devices until about 1490,when the famous Italian painter,Leonardo da Vinci,designed a complete diving suit.”可知,大约在1490年,潜水设备的发明取得比较大的进展,位意大利著名画家设计了套完整的潜水服。据此可知,C项正确。
转载请注明原文地址:https://kaotiyun.com/show/7uGO777K
0
考博英语
相关试题推荐
Nobodyinthecompanypaysattentiontohisopinion,becausewhathehassaidisalwaysmere______.
Ifwewereaskedexactlywhatweweredoingayearago,weshouldprobablyhavetosaythatwecouldnotremember.Butifwehad
Asawayof______themailswhiletheywereaway,theJohnsonsaskedthecleaningladytosendlittleprintedslipsaskingthese
Withoutexposuretothecultural,intellectual,andmoraltraditionsthatareourheritage,weareexcludedfromacommonworld
Informationtechnologythathelpsdoctorsandpatientsmakedecisionshasbeenaroundforalongtime.CrudeonlinetoolslikeW
Wearewritingtothemanager______therepairsrecentlycarriedoutattheaboveaddress.
AlthoughmanypeoplespeakEnglish,theydon’tpronounceitorspellthewordtheyusethesameway.TheUnitedStates,in【C1】__
Thewonderswhichmedicalworkershavealreadybroughtaboutinthediagnosisandtreatmentofdiseasesuggestthatatimemayc
Whatdotheextraordinarilysuccessfulcompanieshaveincommon?Tofindout,welookedforcorrelations.Weknowthatcorrelati
Asshehasakindly,outgoingnature,sheisa_____hostessandhasawidecircleofverygoodfriends.
随机试题
服务投标文件一般内容组成与工程投标文件一般内容组成的相同部分包括()。
明挖扩大基础施工中,黏性土在半干硬或硬塑状态,基坑顶无活荷载,稍松土质,基坑深度不超过0.5m时,可采用()。
投资者(客户)的主要风险有()。
对于制造并提供虚假资料和交易信息债券的回购业务参与者,中国人民银行可采取的措施有()。
回归方程不一定经过的点是()。
李老师所教的大部分学生都喜欢他的领导方式,学生们进行所有的活动都会依据李老师的指示,但学生自身的主动学习和创造能力较差。李老师最可能的领导方式是()。
人类不能穷尽对世界的认识,因此世界是不可知的。()
对某中学初中一年级学生实施了标准化的数学考试,全体学生成绩的平均分为83分,某学生了80分,他数学成绩的Z值为一0.5,则全体考生数学成绩的标准差为()。
ItwasnotuntilthenthatIcametoknowthatknowledgecomesfrompractice.
A—feedbackB—leafobjectsC—physicalsecurityD—keyboardE—flowchart
最新回复
(
0
)