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问题 单项选择题

防腐剂过量属于食品污染的哪一种？（）

A.原料污染

B.保鲜产生的污染

C.制作过程中的污染

D.生物性污染

答案

参考答案：B

解析：防腐剂主要是用来抑制微生物的生长和繁殖，防止保护对象腐敗变质的，即作用是为了保证食品的新鲜，那么防腐剂过量属于保鲜产生的污染。本题选B。

填空题

根据短文内容及首字母提示，填写所缺单词，并将答案填写在相应位置上。

Chuck Wall teaches management and human relations at Bakersfield College. He walked into class one day and told his students that their h   小题1:    was to perform one act of random(任意的) kindness. His students did not understand the assignment(任务), but the professor would not answer their questions. He e   小题2:   his students to find it out for themselves.

One week later, the students entered the classroom excited to s   小题3:  their stories. One student told of distributing blankets to the homeless, another had contacted a long, lost friend, and another student r  小题4:   that he had helped a dog to find its owner. Students were energized(激励) by the homework assignment and wanted other people to be kind too. W  小题5: the support of local businesses, the students made stickers to put on cars that invited people to do something k 小题6: for others. They sold the stickers and decided to donate the money to a center for the blind –not surprising as Professor Wall is blind.

Since then, s  小题7:  kindness activities have been organized in schools all over the world. Many schools organize a Random Acts of Kindness Week, a  小题8:  November 13, to celebrate World Kindness Day. Some schools use each day of Random Acts of Kindness Week to perform d 小题9: kind acts, such as making a new friend, helping someone, doing community service, or raising money for a charity. Students learn to c  小题10:  other people and think about how small actions can make the world a better place.
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选择题
同步卫星离地心距离为r，运行速度率为v1，加速度为a1,地球赤道上的物体随地球自转的向心加速度为a2，第一宇宙速度为v2，地球的半径为R，则下列比值正确的是  （   ） 。

A．=                    B．=

c． =                    D．=

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