Have you heard the old saying “Celestial(天上的) hours, earthly years”? Let me tell you a magical story about twins. Suppose Lucy becomes an astronaut and flies through space in a super-fast rocket, while her twin sister Lily stays on Earth. When Lucy returns after her journey, something amazing happens—Lily might appear older, but Lucy still looks young! Einstein called this the “Twin Paradox①” or Time Dilation(膨胀). Why? Because time slows down when you move super fast.
Of course, time moves a little slower or faster depending on the speed or Earth’s gravity(引力). But the effects are too tiny to notice in our daily life. For example, if you drive very fast, like 100 km/h, time slows by 0.000000001 seconds per hour. You’d never feel it! A pilot who flew for 40 years, ages 0.0005 seconds slower than someone on Earth. Still too small!
Scientists tested the time dilation with two special and the same kind of atomic clocks(原子钟). They put one clock in a plane flying around the world and left the other on the ground. After the trip, the flying clock was a tiny bit behind—just a few microseconds(微秒)! Even though the difference is really tiny, this matters a lot for technology.
Your phone’s GPS uses this secret! Satellites(卫星) high above Earth face two “time tricks”: They move super fast(14,000 km/h), making their clocks slow down by 7 microseconds daily. Being far from Earth’s gravity makes their clocks speed up by 45 microseconds daily.
Engineers subtract(减去) these numbers and fix satellite clocks by 38 microseconds daily. Without this, GPS would guide you wrong by 10 km every day—you might drive into a lake instead of your school! So next time you use a map app, .
Note:① Twin Paradox:“双生子佯谬”是一个有关爱因斯坦狭义相对论的实验现象,借指移动时钟的时间膨胀现象。
( )61. Why is the old saying mentioned at the beginning of the passage?
A. To tell us different ways of seeing time.
B. To explain the point about stars and space.
C. To compare the new technology with time.
D. To introduce the theme of the reading material.
()62. What does “it” in Paragraph 2 refer to?
A. The time dilation.
B. The Earth gravity.
C. The space trip.
D. Our daily life.
()63. What is the writer’s attitude towards the tiny effect in Paragraph 3?
A. He is worried about it.
B. He takes it seriously.
C. He is so crazy about it.
D. He doesn’t care about it.
()64. Which of the following makes use of Time Dilation?

()65. Which of the following can be put in “”?
A. avoid moving a little slower or faster depending on the speed
B. keep testing the time with two special and the same kind of clocks
C. remember to thank those hard-working satellites racing against time in space
D. learn to subtract these numbers and fix satellite clocks by 38 microseconds daily

61. D 【解析】推理判断题。根据第一段“Einstein called this the 'Twin Paradox' or Time Dilation. Why? Because time slows down when you move super fast.”可知,文章开篇这句谚语是为了引出“双生子佯谬”,即时间膨胀这一主题。故选D。
62. A 【解析】代词指代题。根据第二段“Of course, time moves a little slower or faster depending on ... You'd never feel it!”可知,前文围绕时间膨胀展开,速度和地球引力会影响时间的快慢,在日常生活中影响小到难以察觉,“it”指代时间膨胀。故选A。
63. B 【解析】推理判断题。根据第三段“Even though the difference is really tiny, this matters a lot for technology.”可知,即使差别极小,但这对技术很重要,体现作者重视这种微小影响。故选B。
64. D 【解析】图片理解题。根据第四段“Your phone's GPS uses this secret! Satellites high above Earth face two 'time tricks': They move super fast(14,000 km/h), making their clocks slow down by 7 microseconds daily.”可知,卫星受速度和地球引力影响时间,工程师修正卫星时钟。所以和卫星相关的选项利用了时间膨胀。故选D。
65. C 【解析】推理判断题。根据最后一段“Engineers subtract these numbers and fix satellite clocks by 38 microseconds daily. Without this, GPS would guide you wrong by 10 km every day—you might drive into a lake instead of your school!”可知,受时间膨胀影响,卫星移动特别快时,卫星时钟每天会慢7微秒。远离地球引力让卫星时钟每天提速45微秒。工程师校正卫星时钟,GPS才能正常工作,所以当你使用地图应用软件时,要感谢在太空中与时间赛跑的卫星。故选C。