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
A、They built a much lighter rocket. B、They built a much faster rocket. C、They loaded the rocket with enough fuel. D、They built a
A、They built a much lighter rocket. B、They built a much faster rocket. C、They loaded the rocket with enough fuel. D、They built a
admin
2012-09-19
32
问题
Since the beginning of history, people on the earth have always watched the sky and wondered about the things they saw. As centuries of discoveries flew by, it became obvious that humans would not be content to just gaze at the solar system. We wanted to fly into it and explore it as well.
Once again, technology allowed us to accomplish our goal. (33)On October 4, 1957. a Soviet rocket sent the first man-made satellite into space. It was called Sputnik, the Russian word for "traveler". Even though Sputnik was nothing more than a small aluminum ball with a radio inside, it started a whole new era of space exploration.
In May 1961 President John F. Kennedy challenged American scientists to land a person on the moon before the end of the 1960s. (34)In the quest to do this, scientists faced many obstacles. For example, to get a spaceship all the way to the moon and back would demand a rocket engine powerful enough to make the trip. (35)Scientists realized that it would be difficult for one heavy rocket loaded with fuel to reach the moon. Instead, they decided to use a multistage rocket. When the fuel in one stage of the multistage rocket is used up, that stage will fall away. This makes the rocket lighter, and the engine of the next stage can go on providing power and thrust the rocket even faster and higher. As you know, Americans successfully landed on the moon in July 1969. Since then our knowledge of the solar system has increased dramatically.
选项
A、They built a much lighter rocket.
B、They built a much faster rocket.
C、They loaded the rocket with enough fuel.
D、They built a multistage rocket.
答案
D
解析
在制造火箭推进器的过程中,科学家们意识到it would be difficult for one heavy rocket loaded with fuel to reach the moon,所以他们决定使用multistage rocket(多级火箭)。
转载请注明原文地址:https://kaotiyun.com/show/wi57777K
0
大学英语四级
相关试题推荐
Boy,tourismreallyisabigbusinessthesedays.It’s【B1】______.Itinvolveshotels,transportation,restaurants,shops,andth
A、Therearemanyvisitorsthere.B、Therearemanystudentsthere.C、Therearemanyoldstreetsthere.D、Therearemanybicycles
A、Tohelpinternationalstudentspreparetoenterinstitutionsofhigherlearning.B、ToteachstudentshowtouseEnglishinthe
A、Becausehewastoooldtoseewhodidit.B、Becausetheboysrantoofastforhimtocatch.C、Becauseitwasimpossibleforhi
InatimeoflowacademicachievementbychildrenintheUnitedStates,manyAmericansareturningtoJapan,acountryofhigha
Geographyisthestudyoftherelationshipbetweenpeopleandtheland.Geographers(地理学家)compareandcontrast【C1】______places
Geographyisthestudyoftherelationshipbetweenpeopleandtheland.Geographers(地理学家)compareandcontrast【C1】______places
AssoonasitwasrevealedthatareporterforProgressivemagazinehaddiscoveredhowtomakeahydrogenbomb,agroupoffirea
Actuallyalmosteveryworkerhasahighlydevelopedsenseofhowmuchwork______him.
______(我不太想去参加那个音乐会),butIhadtopretendIwanted.
随机试题
医德修养的根本途径是()
A.苦寒B.甘寒C.辛苦温D.甘苦温E.甘辛温理气药的性味多为
按照FSGD0001《压力管道安全技术监察规程——工业管道》中要求,设计工作压力为1MPa的压力管道应划分为()。
组织活动的基本原理是()。
根据《水工建筑物抗冲磨防空蚀混凝土技术规范》DL/T5207—2005,泄水建筑物中水流空化数σ小于()的部位应采取防空蚀措施。
建设项目管理“三项制度”中不包括()。
在贷款质押担保问题上,银行在法律方面要重点考虑的是()。
黄金作为个人理财产品,可以选择的投资方式有()。
作业同步面向用户,而进程同步面向计算机内部资源管理控制。()
Helenlookedatthefinishedpaintingwith______.
最新回复
(
0
)