科目: 来源:同步题 题型:阅读理解
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科目: 来源:同步题 题型:阅读理解
Edmund Halley was an English scientist who lived over 200 years ago. He studied the
observations of comets(彗星) which other scientists had made. The orbit of one
particular comet was a very difficult mathematical problem. He could not figure it out.
Neither could other scientists who dealt with such problems.
However, Halley had a friend named Isaac Newton, who was a brilliant mathematician.
Newton thought he had already worked out that problem, but he could not find the
paper on which he had done it. He told Halley that the orbit of a comet had the shape
of an ellipse(椭圆形).
Now Halley set to work. He figured out(觯决,计算出) the orbits of some of the
comets that had been observed by scientists. He made a surprising discovery. The
comets that had appeared in the years 1531, 1607 and 1682 all had the same orbit.
Yet their appearances had been 75 to 76 years apart.
This seemed very strange to Halley. Three different comets followed the same orbit.
The more Halley thought about it, the more he thought that there had not been three
different comets, as people thought. He decided that they had simply seen the same
comet three times. The comet had gone away and had come back again.
It was an astonislung idea! Halley felt certain enough to make a prediction(顶言 )
of what would happen in the future. He decided that this comet would appear in the
year 1758. There were 53 years to go before Halley's prediction could be tested.
In 1758 the comet appeared in the sky. Halley did not see it, for he had died some
years before. Ever since then that comet had been called Halley's comet, in his honour.
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科目: 来源:期末题 题型:阅读理解
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科目: 来源:广东省模拟题 题型:填空题
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科目: 来源:同步题 题型:阅读理解
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科目: 来源:广东省模拟题 题型:完形填空
完形填空。 | ||||
eBooks still some way away from students Twelve-year-old Tang Yin is one of the earliest students to test a digital textbook in China. The boy said he was a little 1 when he received the monochromatic (单色的) flat device in April, 2010, because he thought it should be a " 2 cool" laptop. But Tang still cherishes (珍爱) his new equipment like "protecting my 3 ," said the fifth grader. After all, not every student has the opportunity to 4 the eBook, which is worth 2,000 yuan, he said. The 50 eBooks, 5 by Taiwan eBook manufacturer Chuanqi Photoelectric Technology in Yangzhou, Jiangsu Province, enable one class at Yangzhou Sanyuanqiao Elementary School to be the 6 group of students in the Chinese mainland to replace their regular textbooks with electronic ones. Out of l,000 students, Tang' s class was the lucky 7 . "Our school could not 8 the project without the company' s donation," said Yuan Shishan, vice-headmaster of the primary school 9 the digital book is considered environmentally friendly, because it replaces paper books and saves money in the long run, the price is much higher than most Chinese 10 can afford. Also, some technical defects, the 11 of taking notes and monochromatic display, make the eBook fail to meet the expectations of students and teachers. "There's still a(n) 12 way to go before the eBook really plays an important role in education," said the headmaster. According to Yuan, the annual average income of a 13 family in Yangzhou is about 20,000 to 30,000 yuan, and neither the parents nor the school can afford the 2,000 yuan 14 book. The school doesn't allow the students to take their eBooks to their homes. The devices are 15 after class, and are locked in the headmaster's office. | ||||
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科目: 来源:同步题 题型:阅读理解
阅读理解。
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科目: 来源:0118 期中题 题型:阅读理解
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科目: 来源:同步题 题型:阅读理解
3. The author suggests that governments will have no excuse for their careless ignorance in the future
because .
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