北约轰炸南联盟时，使用了大量的美制贫铀弹，造成了严重的后果．

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北约轰炸南联盟时，使用了大量的美制贫铀弹，造成了严重的后果．已知贫铀弹中含有的铀-236（236为相对原子质量）是一种放射性元素，其质子数为92，则这种铀原子里中子数与核外电子数之差为______．

答案

核外电子数等于核内质子数等于92，由相对原子质量=质子数+中子数，可知中子数=236-92=144，所以铀原子里中子数与核外电子数之差为144-92=52

故答案为：52

完形填空

What’s your idea about success? Some people say that beginners have all the luck, while others believe that success       only with practice. In fact, I fell both of these statements are not true all the time. Each is true in some ways       not in others.
　　For example, I went to a drawing competition many years ago and        surprisingly. As a prize, I got a film ticket to see “Titanic”. I was really        because it was the first time I had taken part in any competition, Thinking that I might be lucky again, I         joining in other art competitions, ‘But the result was that I        won again. I accepted the fact that the other people had a         artistic ability than I did. Art was not something I was especially interested in and I had never practiced the different art skills. So, the        I produced were not of a very high standard
　　These experiences taught me a lot. Though I might have been lucky       , I also need to put in hard work. As we know,       akes perfect. So I believe success builds on less luck and chance.

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晨间检查的主要目的是防止儿童将传染病及危险品带到所{园}里。检查可在日托儿童每天入园时，整托儿童早晨起床后进行。检查步骤包括一回、二（）、三看、四查。

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