小学生科普说明文作文.doc

小学生科普说明文作文 篇一：科普说明文300 专题十六 阅读理解之科普类说明文 1.【2015·湖北卷】d 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 own challenges. 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 balled （芭蕾）dancer. “i’m an inside guy,” mike hopkins says, who returned from a six-month tour on the international space station. 搃 like to be wrapped up.?leroy chiao, 54, an american retired astronaut after four flights, describes what happens even before you float out of your seat,攜our inner ear thinks your抮e falling . meanwhile your eyes are telling you you抮e standing straight. that can be annoying 梩hat抯 why some people feel sick.?within a couple days 梩ruly terrible days for some 梐stronauts?brains learn to ignore the panicky signals f rom 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抯 why exercise is considered so vital that national aeronautics and space administration (nasa) puts it right on the workday schedule. the focus on fitness is as much about science and the future as it is about keeping any individual astronauts return home, and, more importantly, how to maintain strength 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 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. the y circle around on their bikesc. they exercise in one place for a long time d. they watch a movie while pedaling 65.some astronauts feel sick on the station duri