问题
单项选择题
验证是否产生氧气的方法是（）
A.把燃烧的牙签放在收集气体的玻璃管口
B.把快要熄灭的牙签放到收集气体的玻璃管口
C.看到冒出的气泡就可以验证
D.没有气泡也可以验证
答案
参考答案：B
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验证是否产生氧气的方法是（）
A.把燃烧的牙签放在收集气体的玻璃管口
B.把快要熄灭的牙签放到收集气体的玻璃管口
C.看到冒出的气泡就可以验证
D.没有气泡也可以验证
参考答案：B
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| One night I was sitting in my kitchen half-listening as my 15-year-old son, Tommy quarreled with his 12- year-old brother Kevin. I didn't pay attention when Kevin 1 the stairs with the 2 on his face. About 20 minutes later, as I was walking upstairs I heard Kevin 3 inside the bathroom. I bit my tongue to 4 myself saying, "Come on Kevin, don't be such a 5 ." Instead, I knocked on the door and asked, "Hey, Kevin, do you want a 6 ?" No answer. I 7 again, "Why don't you come out of there?" No answer again. So, joking around, I took hold of a pile of 8 and a pencil and wrote, "If you don't want to talk, we can 9 notes to each other. An hour later I was 10 sitting outside the bathroom with two piles of the cards in front of me. They are cards from Kevin on which he had 11 all his unpleasant feelings into words for me. By this time I don't 12 the rings of my telephone and popular TV show downstairs. One of Kevin's notes said, " 13 in this family cares about me. I am not the youngest, and I am not the 14 , and I am not the 15 . Tommy thinks that I am stupid and Dad wishes he had 16 Kevin as a kid because he's better at baseball. And you never 17 me." 18 came to my eyes. I wrote back, "You know, Kevin, I really do love you and I am sorry I don't always 19 it. I am here for you and you are loved in this family." Since then I try my best to never only 20 my family members any more. Kevin and I have a closer relationship now. | ||||
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