首页
登录
职称英语
[originaltext] Since the beginning of history, people on the earth have alwa
[originaltext] Since the beginning of history, people on the earth have alwa
游客
2024-02-19
3
管理
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://www.tihaiku.com/zcyy/3463736.html
相关试题推荐
[originaltext]Fewbuildingsonearthcancompetewiththelegendarybeauty
[originaltext]Fewbuildingsonearthcancompetewiththelegendarybeauty
[originaltext]Fewbuildingsonearthcancompetewiththelegendarybeauty
[originaltext]TheFrenchareathearttraditionalists.Thoughtheydearlyl
[originaltext]TheFrenchareathearttraditionalists.Thoughtheydearlyl
[originaltext]Peoplewhobuysharesofstockinacompanymaymakemoneyin
[originaltext]W:Whatdoyouplantodoafteryoufinishyouruniversitywork?
[originaltext]W:Whatdoyouplantodoafteryoufinishyouruniversitywork?
[originaltext]W:Bill,isthatreallyyou?Ihaven’tseenyouformonths.M:He
[originaltext]W:Stevecalledtoseewhetherwecangivehimalifttothebeac
随机试题
[originaltext]Interviewer(M)Dr.JoanneGetsy(W)Now,listentoPartOneofthe
有关普通股、优先股的股东权益不正确的是()A.普通股有公司的经营权 B.优先
以下对OSI(开放系统互联)参考模型中数据链路层的功能叙述中描述最贴切的是(
高低温试验后,反光膜表面不应出现裂缝、软化、剥落、皱纹、起泡、翘曲或外观不均匀等
A.生理性萎缩 B.营养不良性萎缩 C.神经性萎缩 D.失用性萎缩绝经期妇
来源为樟科植物的干燥树皮的药材是A.苦楝皮 B.肉桂 C.香加皮 D
项目投资决策的基础是()。A:市场预测 B:市场分析 C:市场战略 D:
王老师是刚刚大学毕业走上教师岗位的新教师,身上依然保留着大学期间我行我素的作风。
_________Mr.Penningtonretires,hewil
在安装工程一切险中,保险人应当赔偿损失的是( )。A.自然磨损 B.维修保养
最新回复
(
0
)