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  3. To understand how astrology works, we should first take a quick look at the sky. Although the stars are at enormous distances, t

To understand how astrology works, we should first take a quick look at the sky. Although the stars are at enormous distances, t

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问题     To understand how astrology works, we should first take a quick look at the sky. Although the stars are at enormous distances, they do indeed give the impression of being affixed to the inner surface of a great hollow sphere surrounding the earth. Ancient people, in fact, literally believed in the existence of such a celestial sphere. As the earth spins on its axis, the celestial sphere appears to turn about us each day, pivoting at points on a line with the earth’s axis of rotation. This daily turning of the sphere carries the stars around the sky, causing most of them to rise and set, but they, and constellations they define, maintain fixed patterns on the sphere, just as the continent of Australia maintains its shape on a spinning globe of the earth. Thus the stars were called fixed stars.
    The motion of the sun along the ecliptic is, of course, merely a reflection of the revolution of the earth around the sun, but the ancients believed the earth was fixed and the sun had an independent motion of its own, eastward among the stars. The glare of sunlight hides the stars in daytime, but the ancients were aware that the stars were up there even at night, and the slow eastward motion of the sun around the sky, at the rate of about thirty degrees each month, caused different stars to be visible at night at different times of the year.
    The moon, revolving around the earth each month, also has an independent motion in the sky. The moon, however, changes it position relatively rapidly. Although it appears to rise and set each day, as does nearly everything else in the sky, we can see the moon changing position during as short an interval as an hour or so. The moon’s path around the earth lies nearly in the same plane as the earth’s path around the sun, so the moon is never seen very far from the ecliptic in the sky. There are five other objects visible to the naked eye that also appear to move in respect to the fixed background of stars on the celestial sphere. These are the planets Mercury, Venus, Mars, Jupiter, and Saturn. All of them revolve around the sun in nearly the same plane as the earth does. So they, like the moon, always appear near the ecliptic. Because we see the planets from the moving earth, however, they behave in a complicated way, with their apparent motions on the celestial sphere reflecting both their own independent motions around the sun and our motion as well.
According to the text, which of the following is true?
选项 A、Scientists can tell the motion of the earth from the motions of five other planets.
B、A fixed star refers to a star that is always stationary on the sky.
C、Ancient people had scant knowledge about the movement of the stars.
D、All the stars on the sky can be seen all year long.
答案A
解析 推理判断题。根据原文以及常识可以知道，恒星自身也是运动的，只是在天球上相对静止，所以应该是relatively stationary。因此[B]错误。[C]说古人对星球的运动缺乏了解，与原文内容相悖。[D]根本不符合常识，可直接排除。只有[A]可以从原文中推断出来。由于地球与那五个星球在同一平面，都围绕地球转动，所以科学家可以根据它们的运动推算出地球的运动。
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