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问题 单项选择题

信息系统和电子政务的安全风险来自于（）

A、物理风险

B、无意错误风险

C、有意破坏风险

D、以上都是

答案

参考答案：D

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自然界各种资源为我们人类提供了赖以生存和发展的基础，我们要珍惜和爱护，合理地开发利用．

（1）为防止空气中CO2含量增加带来的温室效应，法国化学家Paul  Sabatier提出CO2甲烷反应．该反应使CO2和H2在催化剂作用下生成CH4和H2O，请写出该反应的化学方程式为______

（2）海洋是一个巨大的资源宝库．海水经蒸发结晶可获得粗盐．粗盐中含有少量的泥沙等不溶性杂质，实验室里可通过下列步骤制取精盐：溶解→过滤→______（填写操作步骤）．蒸发时玻璃棒的作用是______．

（3）煤和石油是重要的化石燃料，其燃烧的条件是氧气和______；用煤和石油还可以生产许多的合成材料，下列生活用品主要用合成材料制成的是______．

①塑料桶      ②菜刀       ③铁锅       ④电话机       ⑤羊毛衣．
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     从方框中选择合适的词汇，并用其恰当的形式填空，如有需要请组成短语或用变形词或同义词填空。注意动词时态，详见例句。
take  end  with  late  alone  beyond  news  piece  pay  conversation
1. With so much loud music in the restaurant, ________ between us was almost impossible.
2. The son, Johann Strauss the younger, was even more successful than his father. The Blue
    Danube is one of his finest ________ music.
3. ________ report says that five more Ribbons died of bird flu. People in town are in great panic now.
4. He was so angry that he slammed the door and left ________ word.
5. My brother is a pilot, and he ________ to over 300 countries up till now.
6. You have to ________ the book you lost. This is the rule in library.
7. Most people do not choose to work ________ the normal retirement (退休) age.
8. ________ the movie, the nother finally found her lost daughter and gave the baddie (坏人) a hard attack.
9. I heard all ahout the bombs ________: 13 people were badly injured, but no one died.
10. My sister has a lot of interests and hobbies. She doesn't feel ________ at all, though she lives all by herself.
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