题目内容
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. Which of the following is true about the motion of the moon
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One country that is certain of the effect of films on tourism is Australia. The Tourist Office of Queensland say that Crocodile Dundee,【C1】______Paul Hogan, made Australia the popular【C2】______it is today. In the three years after Crocodile Dundee was【C3】______, visitor numbers doubled. 【C4】______what makes people want to visit the place where a movie was filmed In many cases the reason is【C5】______the film makes audiences【C6】______of the existence of a place. 【C7】______the James Bond movie The Man with the Golden Gun was filmed in Phuket, Thailand, most Westerners had never heard of it. Today it is a major destination. Leonardo di Caprio"s film The Beach has【C8】______tourism in another part of Thailand. The film is about the discovery of the most idyllic beach in the world. As a result the Thai authorities are【C9】______a tourist boom in the film"s【C10】______, Koh Phi Phi. Some people are influenced by a movie"s【C11】______as much as its location, especially if it is a romance. Four Weddings and a Funeral has【C12】______that "The Crown" hotel in Amersham has been busy ever【C13】______the movie was first shown. In fact the bedroom where the【C14】______played by Hugh Giant and Andie McDowell spend their first night together is【C15】______for years ahead. "We" ve【C16】______the number of marriage proposals that have been made there, " says the hotel【C17】______. It is not just the tourist boards who are happy【C18】______the influence of films on a destination. Residents of a rather run-down area of London have seen house prices almost double 【C19】______Julia Robert"s romance with Hugh Grant in Notting Hill . Film stars, such as Madonna, who had previously thought of Notting Hill as a good place for a party, have now bought【C20】______there. Perhaps they hope to revive their romances. 【C4】
For mothers-to-be, doctors worldwide advise taking a folic acid supplement. That"s because pregnant women with a deficiency of this vitamin have an increased chance of giving birth to a baby with serious birth defects. Yet a new mouse study shows that folic acid supplementation can itself sometimes increase the risk of birth defects or even cause the death of embryos. Experts caution, however, that the unexpected rodent results are too preliminary to require an immediate change in medical practices until more is known about how the vitamin influences development. People typically obtain folic acid, from consuming leafy vegetables, but not everyone gets enough from their diet, particularly pregnant women. Evidence from randomized clinical trials has shown that babies born to women who double their recommended daily dose of folic acid are between 40% and 50% less likely to have birth defects of the spine, skull, and brain. As a result, the United States has fortified most of its grains with this vitamin since 1998, and a handful of other countries have followed suit. But just how the vitamin influences embryonic growth remains a mystery. So developmental biologist Lee Niswander of the University of Colorado, Denver, set out to investigate folic acid supplementation in mice genetically predisposed to giving birth to embryos with neural tube defects. She and her colleagues fed five such strains of mutant mice food containing either 2 or 10 mg of folic acid per kilogram, which created a range of blood levels of the vitamin equivalent to that in the U. S. population. To the surprise of the researchers, in three of the five strains, the extra folic acid seemed to worsen the severity of birth defects rather than remedy them. In one of the mutant lines, eating the higher folic acid diet long term increased the chance that young were born with neural tube defects from 20 % to 60 % . And for another strain, many of whose embryos don"t naturally survive until birth due to their genetic problems, eating the higher folic acid food significantly increased the percentage of lost embryos. Niswander says it is clear that folic acid is good for human fetuses, but the new study makes her wonder whether high levels of the vitamin may be harmful in some circumstances. Still, she stresses that more data are needed before any serious reconsideration of how much folic acid to recommend for impending mothers. Roy Pitkin, a retired researcher of University of California, Los Angeles, who specialized in pregnant women"s nutrition and chaired an Institute of Medicine panel that in 2000 reviewed folic acid"s health effects also cautions against a rush to judgment: "It would really be throwing the baby out with the bath water to say that because of this one mouse study, we are going to question the food fortification. " Roy Pitkin would most probably agree that
For mothers-to-be, doctors worldwide advise taking a folic acid supplement. That"s because pregnant women with a deficiency of this vitamin have an increased chance of giving birth to a baby with serious birth defects. Yet a new mouse study shows that folic acid supplementation can itself sometimes increase the risk of birth defects or even cause the death of embryos. Experts caution, however, that the unexpected rodent results are too preliminary to require an immediate change in medical practices until more is known about how the vitamin influences development. People typically obtain folic acid, from consuming leafy vegetables, but not everyone gets enough from their diet, particularly pregnant women. Evidence from randomized clinical trials has shown that babies born to women who double their recommended daily dose of folic acid are between 40% and 50% less likely to have birth defects of the spine, skull, and brain. As a result, the United States has fortified most of its grains with this vitamin since 1998, and a handful of other countries have followed suit. But just how the vitamin influences embryonic growth remains a mystery. So developmental biologist Lee Niswander of the University of Colorado, Denver, set out to investigate folic acid supplementation in mice genetically predisposed to giving birth to embryos with neural tube defects. She and her colleagues fed five such strains of mutant mice food containing either 2 or 10 mg of folic acid per kilogram, which created a range of blood levels of the vitamin equivalent to that in the U. S. population. To the surprise of the researchers, in three of the five strains, the extra folic acid seemed to worsen the severity of birth defects rather than remedy them. In one of the mutant lines, eating the higher folic acid diet long term increased the chance that young were born with neural tube defects from 20 % to 60 % . And for another strain, many of whose embryos don"t naturally survive until birth due to their genetic problems, eating the higher folic acid food significantly increased the percentage of lost embryos. Niswander says it is clear that folic acid is good for human fetuses, but the new study makes her wonder whether high levels of the vitamin may be harmful in some circumstances. Still, she stresses that more data are needed before any serious reconsideration of how much folic acid to recommend for impending mothers. Roy Pitkin, a retired researcher of University of California, Los Angeles, who specialized in pregnant women"s nutrition and chaired an Institute of Medicine panel that in 2000 reviewed folic acid"s health effects also cautions against a rush to judgment: "It would really be throwing the baby out with the bath water to say that because of this one mouse study, we are going to question the food fortification. " According to paragraph 2, randomized clinical trials have
One country that is certain of the effect of films on tourism is Australia. The Tourist Office of Queensland say that Crocodile Dundee,【C1】______Paul Hogan, made Australia the popular【C2】______it is today. In the three years after Crocodile Dundee was【C3】______, visitor numbers doubled. 【C4】______what makes people want to visit the place where a movie was filmed In many cases the reason is【C5】______the film makes audiences【C6】______of the existence of a place. 【C7】______the James Bond movie The Man with the Golden Gun was filmed in Phuket, Thailand, most Westerners had never heard of it. Today it is a major destination. Leonardo di Caprio"s film The Beach has【C8】______tourism in another part of Thailand. The film is about the discovery of the most idyllic beach in the world. As a result the Thai authorities are【C9】______a tourist boom in the film"s【C10】______, Koh Phi Phi. Some people are influenced by a movie"s【C11】______as much as its location, especially if it is a romance. Four Weddings and a Funeral has【C12】______that "The Crown" hotel in Amersham has been busy ever【C13】______the movie was first shown. In fact the bedroom where the【C14】______played by Hugh Giant and Andie McDowell spend their first night together is【C15】______for years ahead. "We" ve【C16】______the number of marriage proposals that have been made there, " says the hotel【C17】______. It is not just the tourist boards who are happy【C18】______the influence of films on a destination. Residents of a rather run-down area of London have seen house prices almost double 【C19】______Julia Robert"s romance with Hugh Grant in Notting Hill . Film stars, such as Madonna, who had previously thought of Notting Hill as a good place for a party, have now bought【C20】______there. Perhaps they hope to revive their romances. 【C1】
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