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共用题干 An Expensive MistakeIs there water on the planet Mars?Is there life in Mars? Was there ever life on Mars? Scientists from NASA wanted to know the answers to these questions.They built a space-craft to travel around Mars and get information.The spacec

题目
共用题干
An Expensive Mistake
Is there water on the planet Mars?Is there life in Mars? Was there ever life on Mars? Scientists from NASA wanted to know the answers to these questions.They built a space-craft to travel around Mars and get information.The spacecraft was called the Mars Climate Orbiter.
The Mars Climate Orbiter left for Mars in December 1998.The trip took nine and a half months.At first,everything was fine.However,when the Orbiter got near Mars,something terrible happened.The spacecraft didn't go to the right place.It went too close to Mars.It was too hot for the Orbiter there.The spacecraft couldn't function correctly.Suddenly,it stopped sending messages to NASA.The Orbiter was lost.
How could this terrible thing happen? How did the Orbiter get closer to Mars than the scientists planned?Finally,they found the answer.Two teams of scientists worked together on the Orbiter.One team was in England,and one team was in United States.There were many similarities in the way they worked,but there was one important difference:The teams used different guidelines for measuring things.The United States team used the metric system(公制).The other team used the English system.
Because they used different systems,the scientists made a mathematical mistake.The Orbiter's orbit(the shape and pattern of its path)around Mars was not correct.The scientists put the Orbiter on the wrong path.The Orbiter got too close and too hot.And it stopped functioning.
Why didn't anybody see the mistake before it was too late? Many things contributed to the problem.One thing was that NASA scientists and mathematicians were working on two other spacecrafts at the same time.This was a challenge,and they were very tired from working long hours.
The Mars Climate Orbiter cost$94 million to build.It also cost a lot of money to try to find the lost Orbiter in space.In addition,NASA's research on the cause of the problem was very expensive.This wasn't the first time that two different measurement systems caused mistakes in scientific projects.However,the Mars Climate Orbiter was definitely the most expensive mistake of all!

When did the Orbiter's problem begin?
A:Right after it left for Mars.
B:When it got near Mars.
C:Right after it landed on Mars.
D:When it returned to Earth.

相似考题
参考答案和解析
答案:B
解析:
题干意为“NASA建造火星气候轨道器以获取关于火星上可能有生命的信息。”短文第一段提到,“火星上有水吗? 火星上有生命吗? 曾经是否有生命? NASA的科学家想要知道这些问题的答案。他们建造了航天器绕火星飞行以获取这些信息。航天器的名字叫火星气候轨道器。”故选A。
题干意为“轨道器需要多长时间接近火星? 不到一年。”短文第二段前两句提到,火星气候轨道器于1998年12月向火星进发,旅程用了九个半月。故此选B。
题干意为“轨道器什么时候开始出现问题? 当它接近火星的时候。”短文第二段第三、四句提到,起初一切正常,然而当轨道器接近火星的时候,糟糕的事情发生了。故选B。
题干意为“是什么导致了轨道器的问题?科学家用了不同的测量系统。”短文第三段提出,有两组科学家一起开展关于轨道器的工作,一组在英国,另一组在美国。这两组科学家的工作方式大部分是相似的,但有一点重要的不同,那就是他们使用了不同的测量体系,美国组用的是公制,而英国组用的是英制,故选D。
题干意为“为什么NASA的科学家没有在轨道器前往火星前发现问题?”短文第五段第三、四句指出,其中的一个原因是,NASA的科学家和数学家在研究火星气候轨道器的同时还在研究另外两台航天器,长时间的工作让他们非常疲惫。故选D。