首页
财务会计
医药卫生
金融经济
考公考编
外语考试
学历提升
职称考试
建筑工程
IT考试
其他
登录
职称考试
下面有 3 篇短文,每篇短文后有 5 道题。请根据短文内容,为每题确定 1 个最佳选项。 The Hyper-X The Hyper-X (超...
下面有 3 篇短文,每篇短文后有 5 道题。请根据短文内容,为每题确定 1 个最佳选项。 The Hyper-X The Hyper-X (超...
admin
2020-12-24
24
问题
下面有 3 篇短文,每篇短文后有 5 道题。请根据短文内容,为每题确定 1 个最佳选项。
The Hyper-X
The Hyper-X (超音速飞机)recently broke the record for air-breathing jet planes when it traveled at a Hypersonic speed (超音速) of seven times the speed of sound. That’s about 5,000 miles per hour. At this speed, you’d get around the world — flying along the equator
(赤道)-in less than 5 hours.
The Hyper-X is an unmanned, experimental aircraft just 12 feet long. It achieves hypersonic speed using a special sort of engine known as a scramjet (超音速冲压式喷气发动机).
For an engine to burn fuel and produce energy, it needs oxygen. A jet engine, like those on passenger airplanes, gets oxygen from the air. A rocket engine typically goes faster but has to carry its own supply of oxygen. A scramjet engine goes as fast as a rocket, but it doesn’t have to carry its own oxygen supply.
A scramjefs special design allows it to obtain oxygen from the air that flows through the engine. And it does so without letting the fast-moving air put out the combustion flames. However, a scramjet engine works properly only at speeds greater than five times the speed of sound.
A booster rocket (助推火箭)carried the Hyper_X to an altitude of about 100,000 feet for its test flight. The aircrafts record-beating flight lasted just 11 seconds. That brief journey on March27 makes a major milestone on the way to a new breed of very, fast airplanes, says Werner J. A. Dahm of the University of Michigan in Ann Arbor. In the future, engineers predict, airplanes equipped with scramjet engines could transport cargo quickly and cheaply to the briijilk (边缘)of space. Such hypersonic jets could carry passengers anywhere in the world in just a few hours.
Out of the three experimental Hyper-X aircrafts built for NASA, only one is now left. The agency has plans for another 11-second hypersonic flight,this time at 10 times the speed of sound.
What does NASA plan to do?
选项
A To build one more Hyper-X aircraft.
B To carry out three more Hyper-X experiments
C To make the aircraft fly higher and longer.
D To test another hypersonic flight at 10 times the speed of sound.
答案
D
解析
转载请注明原文地址:https://ti.zuoweng.com/ti/LMlQKKKQ
相关试题推荐
下面的短文有15处空白,请根据短文内容为每处空白确定1个最佳选项。 YoungAdultsWhoExerciseGetHigher...
下面的短文有15处空白,请根据短文内容为每处空白确定1个最佳选项。 YoungAdultsWhoExerciseGetHigher...
下面的短文有15处空白,请根据短文内容为每处空白确定1个最佳选项。 YoungAdultsWhoExerciseGetHigher...
下面的短文有15处空白,请根据短文内容为每处空白确定1个最佳选项。 YoungAdultsWhoExerciseGetHigher...
下面的短文有15处空白,请根据短文内容为每处空白确定1个最佳选项。 YoungAdultsWhoExerciseGetHigher...
下面的短文有15处空白,请根据短文内容为每处空白确定1个最佳选项。 YoungAdultsWhoExerciseGetHigher...
下面的短文有15处空白,请根据短文内容为每处空白确定1个最佳选项。 YoungAdultsWhoExerciseGetHigher...
下面的短文有5处空白,短文后有6个句子,其中5个取自短文,请根据短文内容将其分别放回原有位置,以恢复文章原貌。 Mt.DesertIs...
下面的短文有5处空白,短文后有6个句子,其中5个取自短文,请根据短文内容将其分别放回原有位置,以恢复文章原貌。 Mt.DesertIs...
下面的短文有5处空白,短文后有6个句子,其中5个取自短文,请根据短文内容将其分别放回原有位置,以恢复文章原貌。 Mt.DesertIs...
随机试题
下列B超检查宜在清晨空腹条件下进行的是( )。 A、甲状腺 B、肝脏 C
2×19年3月10日,甲公司销售一批材料给乙公司,货款共计113万元,款项尚未收
《高桩码头设计与施工规范》JTS167-1-201013.3.3条规定离岸结构
女性患者,37岁,急性阑尾炎术后4天,出现腰部下坠不适,总有便意、排便不尽感;查
下列选项中,不属于引起房地产价格上升的原因的是( )。
治疗慢性下颌下腺炎可采用
下列属于政府履行职能的是()。A.中共海淀区委发出学好中共十七大精神的号召B.清华园街道某居民委员会修建老年人文化娱乐活动中心C.海淀区政府召开创建食品安
心理防卫机制
下列关于酸雨危害的说法,错误的是( )。A.损坏文物古迹B.造成土壤污染C.影响城市景观D.导致气温升高
运输高致病性病原微生物菌(毒)种或者样本,应当由不小于几人的专人护送( )A.2人B.3人C.4人D.5人E.1人