题干

短周期元素 A、B、C、D、E 的原子序数依次增大;A 的一种核素在考古时常用来鉴定一些文物的年代,B的氢化物的水溶液呈碱性;C、D为金属元素,且D原子最外层电子数等于其 K 层电子数;若往 E 单质的水溶液中滴加少量紫色石蕊试液,可观察到先变红后褪色.下列说法中,正确的是(   )

A:B的最高价氧化物对应的水化物的酸性比E强

B:某物质焰色反应呈黄色,该物质一定是含C的盐

C:向D单质与沸水反应后的溶液中滴加酚酞,溶液变红

D:B的氢化物的沸点一定高于A的氢化物

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C

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    “Who can ever have imagined someone like me would make it this far?” asked Chad Wood last week during his high school graduation speech as the best student. Chad offered1to his fellow classmates to never give up---and the words2much more to himself. That's because Chad is deaf, and he told the story of the serious troubles he3to graduate first in his class at Harrison High school in Kennesaw, Georgia.

    Chad didn't start to4until he was 5, according to his mother, Pam Wood. Although her son was5a disadvantage, she was determined not to treat him6. “I've expected him to do everything every other kid does, and I saw no7why he couldn't,” she told ABC News. “And if he8the first time, we just tried again.”

    Chad, 17, worked hard throughout school,9no special treatment but sitting at the front of the class and using a special audio system so he could hear the teacher. All his hard work10. He received full school fare to Vanderbilt University. “Deafness had taught me a lesson to never11,” he said in the speech. “Not when the experts tell you it cannot be done. Not when you have12so far behind that escaping seems the only way 13. Not when achieving your dreams seems an entire14.”

    Chad spoke for about four minutes, after which he received a standing applause from the class and15messages from family, friends and strangers. “They've been sending me messages on Facebook, email, they've been talking to me in person telling me how it had a16on their lives and how they're really17by it,” Chad told ABC News. “It feels18. Seeing that my words19have a power on someone and that they want to work harder because of my words makes me feel20.”