下列说法正确的是（ ）
A．一种元素可以形成几种单质
B．一种单质可以由几种元素组成
C．同种元素组成的单质性质完全相同
D．同种单质的性质完全相同
A、同一种元素可以组成不同的单质．例如碳元素组成的单质有：C60、C90、C240等．故A正确；
B、一种单质只能由一种元素组成．故B错误；
C、同种元素组成的单质性质不一定相同，例如金刚石和石墨是碳的同素异形体，它们的性质不同．故C错误；
D、同种单质的性质不一定完全相同．例如碳单质常温下化学性质稳定，而高温时具有还原性和可燃性，前后性质不同．故D错误．
故选A．
The school was across the street from our home and I would often watch the kids as they played on the playground. She seemed so small as she pushed her way 36 the crowd of boys on the playground. She 37 from them all. I began to notice her at other times, basketball in hand, playing 38 . She would practice dribbling（运球）and shooting over and over again, sometimes until 39 . One day I asked her 40 she practiced so much. She looked 41 in my eyes and without a moment of hesitation she said, “ I want to go to college. The only way I can 42 is to get a scholarship. I am going to play college basketball. I want to be the best. My daddy told me if the dream is 43 enough, the facts don’t count.” Well, I had to give in to her—she was 44 . One day, I saw her sitting in the grass, head 45 in her arms. I walked toward her and 46 asked what was the matter. “Oh, nothing,” came a soft reply, “ I am just too short.” The coach told her that at her height she would probably 47 get to play for a top ranked team, 48 offered a scholarship. So she 49 stop dreaming about college. She was 50 and I sensed her disappointment. I asked her if she had talked to her dad about it yet. She told me that her father said those coaches were wrong. They just did not 51 the power of the dream. He told her 52 she really wanted to pay for a good college, if she truly wanted a scholarship, 53 could stop her except one thing---her own attitude. He told her again, “If the dream is big enough, the facts don’t count.” The next year, as she and her team went to the Northern California Championship game, she was 54 by a college recruiter(招聘人员). She was indeed offered a scholarship. She was going to get the college education that she had 55 and worked for all those years.
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