题干

实验室用加热氯酸钾制取氧气的主要操作有:①装药品;②固定装置;③检查装置的气密性;④连接仪器;⑤加热;⑥收集气体;⑦撤酒精灯;⑧从水槽中撤出导气管。正确的操作顺序是(    )

A:③④①②⑤⑥⑧⑦

B:③④①②⑤⑥⑦⑧

C:④③①②⑤⑥⑧⑦

D:④③①②⑤⑥⑦⑧

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C

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    Daniel was born in New Orleans, LA., in 1962, slow to walk and talk, and short. He was the tiniest in his class, but he developed a warm, outgoing nature and was popular with his peers(同龄人). And he became skillful at sports.

    Baseball gave him his earliest challenge. He was an excellent players in Little League. At graduation, the coach named Daniel the team's most valuable player.

    His finest hour, though, came at a school science meeting. He entered an exhibit explaining how the circulatory system works. It was traditional, especially compared to(与…相比)the modern, computerized, blinking-light models entered by other students. My wife, Sara, felt embarrassed for him.

    It turned out that the other kids had made their exhibits. As the judges went on their rounds, they found that these other kids couldn't answer their questions. Daniel answered every one. When the judges awarded the Albert Einstein Plague for the best exhibit, they gave it to him.

    By the time Daniel left for college he stood six feet tall and weighed 170 pounds. He was in superb condition, but he quit baseball for English literature. I was sorry that he would not develop his athletic talent, but proud that he had made such a satisfactory decision.

    One day I told Daniel that the great failing in my life had been that I didn't take a year or two off to travel when I finished college. This is the best way, to my way of thinking, to broaden oneself. Once I had married and begun working, I found that the dream of living in another culture had disappeared. Daniel thought about this. After graduation, he worked as a waiter at college, a bike messenger and a house painter. With the money he earned, he had enough to go to Paris.

    The night before he was to leave, I tossed in bed. I was trying to figure out something to say. Nothing came to mind. Maybe, I thought, it wasn't necessary to say anything.