Theoddnessoflifeinspaceneverquitegoesaway．Herearesomeexamples．Firstconsidersomethingassimpleassleep．Itspositionpresentsitsownchallenges．Themainquestioniswhetheryouwantyourarmsinsideoroutsidethesleepingbag

Question

The oddness of life in space never quite goes away．Here are some examples．
First consider something as simple as sleep．Its position presents its ownchallenges．The main question is whether you want your arms inside or outside the sleeping bag．If you leave your arms out，they float free in zero gravity，often giving a sleeping astronaut the look of a funny ballet （芭蕾） dancer．“I’m an inside guy，”Mike Hopkins says，who returned from a six-month tour on the International Space Station．“I like to be wrapped up．”
On the station，the ordinary becomes strange．The exercise bike for the American astronaut has no handlebars．It also has no sear．With no gravity，it’s just as easy to pedal violently．You can watch a movie while you pedal by floating a microcomputer anywhere you want．Without gravity to help circulate air，the carbon dioxide you exhale（呼气）has a tendency to form an invisible（隐形的）cloud around your head．You can end up with whatastronauts call a carbon-dioxide headache．
Leroy Chiao，54，an American retiredastronaut after four flights，describes what happens even before you float out of your seat．“Your inner ear thinks you’re falling．Meanwhile your eyes are telling you you’re standing straight．That can be annoying-that’s why some people feel sick．”Within a couple of days-truly terrible days for some-astronauts’brains learn to ignore the panicky signals from the inner ear，and space sickness disappears．
Space travel can be so delightful but at the same time invisibly dangerous．For instance，astronauts lose bone mass．That’s why exercise is considered so vital that National Aeronautics and Space Administration（NASA） puts in right on the workdayschedule．The focus on fitness is as much about science and the future as it is about keeping any individualastronaut healthy．NASA is worried about two things：recovery time once astronauts return home，and，more importantly，how to maintainstrength and fitness for the two and a half years or more that it would take to make a round-trip to Mars．
63．What is the major challenge to astronauts when they sleep in space？___
A．Deciding on a proper sleep position．
B．Choosing a comfortable sleeping bag．
C．Seeking a way to fall asleep quickly．
D．Finding a right time to go to sleep．
64．The astronauts will suffer from a carbon-dioxide headache when___？
A．they circle around on their bikes
B．they use microcomputers without a stop
C．Theyexercise in one place for a long time
D．they watch a movie while pedaling
65．Some astronauts feel sick on the station during the first few days because___？
A．their senses stop working
B．they have to stand up straight
C．they float out of their seats unexpectedly
D．their brains receive contradictory messages
66．One of NASA’s major concerns about astronauts is___．
A．how much exercise they do on the station
B．how they can remain healthy for long in space
C．whether they can recover after returning home
D．whether they are able to go back to the station．

Answer 1

63．A   细节理解题．根据第二段第一、二句“First consider something as simple as sleep．Its position presents itsown challenges．”可知在太空睡觉时，对宇航员来说主要的挑战在于恰当的睡眠姿势．故选A项．
64．C   细节理解题．根据第三段中“But station residents have to be careful aboutstaying in one place too long．…You can end up with what astronauts call acarbon-dioxide headache”可知宇航员在一个地方运动久了会出现碳毒性头痛．故选C项．
65．D   细节理解题．根据第四段中“Your inner ear thinks you’re failing．Meanwhileyour eyes are telling you you’re standing straight．That can be annoying-that’swhy some people feel sick．”可知宇航员在大脑接收到矛盾的信息时会感到恶心．故选D项．
66．B  细节理解题．根据最后一段倒数第一、二句“The focus on fitness is as much about science andthe future as is about keeping any individual astronaut healthy…NASA is worriedabout two things：…and，more importantly，how maintain strength and fitness…”可知美国国家宇航局对宇航员主要的担心之一是如何在太空长久地保持健康．故选B项．