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
By the 1820’s in the United States, when steamboats were common on western waters, these boats were mostly powered by engines bu
By the 1820’s in the United States, when steamboats were common on western waters, these boats were mostly powered by engines bu
admin
2009-03-16
98
问题
By the 1820’s in the United States, when steamboats were common on western waters, these boats were mostly powered by engines built in the West (Pittsburgh, Cincinnati, or Louisville), and of a distinctive western design specially suited to western needs. The first steam engines 【21】______ practical use in England and the United States were 【22】______ low-pressure design. This was the type first 【23】______ by James Watt, then manufactured by the firm of Boulton and Watt. Steam was 【24】______ in a large, double-acting vertical cylinder, but the steam reached only a few pounds of pressure per square inch. It was low-pressure engines of this type that 【25】______ first introduced into the United States by Robert Fulton. He 【26】______ such a Boulton and Watt engine from England to run the Clermont. But this type of engine was ,expensive and complicated, 【27】______ many precision-fitted moving parts.
The engine that became standard on western steamboats was of a different and 【28】______ design. It was the work primarily of an unsung hero of American industrial progress, Oliver Evans (1755-1819), the 【29】______ son of a Delaware farmer. Evans early became 【30】______ by the possibilities of mechanized production and steam power. As early as 1802 he 【31】______ a stationary steam engine of high-pressure design in his mill. Engines of this type were not 【32】______, but before Evans they were generally considered 【33】______ and dangerous. Within a decade the high-pressure engine, the new type, had become standard on western waters. Critics 【34】______ of western conditions often attacked it as wasteful and dangerous.
But people who really knew the Ohio, the Missouri, and the Mississippi 【35】______, with good reasons, that it was the only engine for them. In 【36】______ western rivers the weight of vessel and engine 【37】______ important; a heavy engine added to the problem of navigation. The high-pressure engine was 【38】______lighter in proportion to horsepower, and, with less than half as many moving parts, was much easier and cheaper to repair. The main advantages of low-pressure engines were safe operation and 【39】______ of fuel consumption, 【40】______ of which meant much in the West.
选项
A、on
B、by
C、for
D、in
答案
D
解析
转载请注明原文地址:https://kaotiyun.com/show/ePPd777K
本试题收录于:
公共英语四级笔试题库公共英语(PETS)分类
0
公共英语四级笔试
公共英语(PETS)
相关试题推荐
Answerquestions71~80byreferringtothefollowinggames.Note:AnswereachquestionbychoosingA,B,CorDandmarkit
Answerquestions71~80byreferringtothefollowinggames.Note:AnswereachquestionbychoosingA,B,CorDandmarkit
What’stheaverageincreaseperyearofforeignstudentpopulationintheperiodbetween1985and1990intermsofpercentage?
What’stheaverageincreaseperyearofforeignstudentpopulationintheperiodbetween1985and1990intermsofpercentage?
Whatdoesthelecturemainlyconcern?
A=TheRoleofaTeacherB=TheTaskofaTeacherC=AGoodTeacherInwhichpassage...TheRoleofaTeacherTeach
A=TheRoleofaTeacherB=TheTaskofaTeacherC=AGoodTeacherInwhichpassage...TheRoleofaTeacherTeach
Whatarethespeakersdoing?
"Junkscience"ishowElliotMorley,Britain’sministerresponsibleforgeneticallymodifiedfarming,describesstudiesthatcla
"Junkscience"ishowElliotMorley,Britain’sministerresponsibleforgeneticallymodifiedfarming,describesstudiesthatcla
随机试题
涂装作业、储存场所严禁明火。()
A.温肾纳气B.调经止痛C.散结消滞D.杀虫疗癣E.燥湿化痰川楝子除行气止痛外,又能
导游人员的问候往往会给游客留下深刻的印象,是游客头脑中对导游人员“第一印象”的重要组成部分。导游人员在与外国旅游者打招呼时,一般应采用中国式的招呼语,像“您吃了吗?”“您上哪去呀?”以表达亲切。()
某教师在教授新课之前让学生复习上节课学的生字“站”,并且告诉学生,右边的“占”正好是今天要学的生字“钻”的右边部分,于是学生再学“钻”这个字的时候就容易多了,这位教师运用了()原则来进行教学。
邓小平关于社会主义本质的科学概括,为我们坚持公有制而又完善和发展公有制指明了正确的方向。()
引申
France,whichpridesitselfastheglobalinnovatoroffashion,hasdecideditsfashionindustryhaslostanabsoluterighttod
WhydoesDavidgotoProfessorSmithforhelp?
Virtuallyeverythingastronomersknownaboutobjectsoutsidethesolarsystemisbasedonthedetectionofphotons-quantaofele
Questions11-14CompletethefollowingsentencesusingNOMORETHANTHREEWORDSforeachgap.
最新回复
(
0
)