问题
选择题
瓦斯中甲烷与氧气的质量比为1︰4时极易发生爆炸，则此时甲烷与氧气的体积比是（ ）
A．1︰4
B．1︰2
C．1︰1
D．2︰1
答案
答案：B
甲烷与氧气的质量比为1︰4即可得物质的量比为1：2，相同条件下体积比为物质的量比，所以正确选项为B；
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瓦斯中甲烷与氧气的质量比为1︰4时极易发生爆炸，则此时甲烷与氧气的体积比是（ ）
A．1︰4
B．1︰2
C．1︰1
D．2︰1
答案：B
甲烷与氧气的质量比为1︰4即可得物质的量比为1：2，相同条件下体积比为物质的量比，所以正确选项为B；
When I was fifteen, I announced to my English class that I was going to write my own books. Half the students sneered（冷笑）, the 36 nearly fell out of their chairs laughing. “Don’t be silly, only 37 can become writers, ” the English teacher said, “And you are getting a D this term. ” I was so 38 that I burst into tears. That night I wrote a short 39 poem about broken dreams and mailed it to the newspaper. To my 40 , they published it and sent me two dollars. I was a published and 41 writer. I showed my teacher and fellow students. They 42 . “Just plain dumb luck. ” the teacher said. I tasted 43 and I’d sold the first thing I’d ever written. That was more than any of them had done and if it was just dumb luck, that was 44 with me. During the next two years I sold dozens of 45 , letters, jokes and recipes. By the time I 46 from high school, with a C minus average, I had scrapbooks（剪贴簿） filled with my published works. I 47 mentioned my writing to my teachers, friends or my family again. They were dream killers and 48 people must choose between their friends and their dreams, they must always choose their 49 . I had four children at the time, and the oldest was only four. I wrote what I felt. It 50 nine months, just like a pregnant woman. I mailed it without a self addressed stamped 51 and without making a copy of the manu script. A month later I received a（n） 52 , and a request to start working on another book. The worst year I earned two dollars. In my best year I earned 36, 000 dollars. 53 years I earned between five thousand and ten thousand. No, it isn’t enough to live 54 , but it’s still more than I’d make working part time. People ask what college I 55 , what degrees I had and what qualifications I have to be a writer. The answer is： “None. ” I just write. I’m not a genius.
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