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
58
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://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
说明:假设你是王亮,请用下面提供的信息写一封自荐信。时间:3月12日内容:1.写信原因:在网上看到TotalTrade公司招聘销售经理;2.自我介绍:
[originaltext]W:Idon’tknowtothankyou:itsoundstoogladtobetrue,butI
WirelessChargingMayTakePlaceofWiredChargingA)Lastmonth,
增量预算是指不参照本年或以前年度情况,完全安照明年的每一项计划活动和事项进行预算
在VLAN中,如果一个VLAN跨越多个交换机,则属于同一VLAN的工作站要通过
如果市场的抗风险能力越强,则市场风险溢酬的数值就会()。A.越小 B.越大
不属于人体实验的道德原则是A.符合科学的原则 B.知情同意的原则 C.实事求
中药五味子中所含的主要木脂素是A.单氧环木脂素 B.新木脂素 C.联苯环辛烯
《中小学教师职业道德规范》规定了中小学教师所应遵守的职业道德规范,下列没有涉及的
(2019年)某项目环境影响评价需要对环境空气质量进行现状补充监测,下列监测布点
最新回复
(
0
)