问题
单项选择题
伽利略以前的学者认为：物体越重下落得越快，伽利略等一些物理学家否定了这种看法。如图所示，在一支玻璃管中放一片羽毛和一个玻璃球，迅速倒置玻璃管，可以看到玻璃球先于羽毛到达底端，这主要是因为（）
A.玻璃的重量比羽毛重
B.玻璃的密度比羽毛大
C.玻璃和羽毛的材料不同
D.它们受到了空气阻力的影响
答案
参考答案：D
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伽利略以前的学者认为：物体越重下落得越快，伽利略等一些物理学家否定了这种看法。如图所示，在一支玻璃管中放一片羽毛和一个玻璃球，迅速倒置玻璃管，可以看到玻璃球先于羽毛到达底端，这主要是因为（）
A.玻璃的重量比羽毛重
B.玻璃的密度比羽毛大
C.玻璃和羽毛的材料不同
D.它们受到了空气阻力的影响
参考答案：D
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| Mark Gibson is a former gymnastics coach who once worked with many excellent athletes. He often tells a wonderful story about a 15-year-old 1 girl, Cindy, whose attitude brought out the best in everyone. Cindy wasn't a great 2 , but when she was in the gym, everyone complained less, worked harder, and, not 3 , achieved more. Cindy was such a powerful motivator 4 she could see nothing. When it was her turn to do the vault(跳马), mother would also 5 alongside her, and tell her how close she was to the vault. When her mom said, "Vault!", Cindy would reach out and jump, 6 her mother and herself. Cindy loved the sport and kept 7 because she and her mom refused to be defeated by her 8 . Mark called her the most 9 member of the team, not because of her 10 ability, but because of her heart and because she 11 a standard of perseverance and courage that inspired others to get more out of themselves. Everyone who 12 her work hard to be the best 13 how much more they could get out of themselves. This is leadership-leadership by 14 . And we see this sort of leadership not only in 15 but also in families and in the workplace. Often the most important members of the team are not the 16 , mos t skilled, or most powerful. Instead, their 17 is in their attitude and their ability to inspire and 18 others with their optimism, enthusiasm, and determination. People who know how to get the best out of themselves get the best of others. There's no doubt that Cindy's 19 has a great effect on her teammates. A person's personality matters most because it comes from within and does not depend on 20 alone. | ||||
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