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问题 判断题

非致病菌一般不引起疾病，由于其中多数为腐败菌，因此不是间接估测食品变质可能性及评价食品卫生质量的重要指标，仅仅是研究食品腐败变质的原因、过程及控制措施的主要对象。( )

答案

参考答案：错

解析： 非致病菌一般不引起疾病，由于其中多数为腐败菌，因此它是间接估测食品变质可能性及评价食品卫生质量的重要指标，也是研究食品腐败变质的原因、过程及控制措施的主要对象。

问答题

(B)


Directions: Translate the following passage into Chinese.
A new era is upon us. Call it what you will: the service economy, the information age, the knowledge society. It all translates to a fundamental change in the way we work. Already we’re partly there. The percentage of people who earn their living by making things has fallen dramatically in the Western World. Today the majority of jobs in America, Europe and Japan (two thirds or more in many of these countries) are in the service industry, and the number is on the rise. More women are in the workforce than ever before. There are more part-time jobs. More people are sell-employed. But the breadth of the economic transformation can’t be measured by numbers alone, because it also is giving rise to a radical new way of thinking about the nature of work itself. Long-held notions about jobs and careers, the skills needed to succeed, even the relation between individuals and employers—all these are being challenged.
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选择题
如图所示，在x轴上方存在着垂直于纸面向里、磁感应强度为B的匀强磁场，一个不计重力的带电粒子从坐标原点O处以速度v进入磁场，粒子进人磁场时的速度方向垂直于磁场且与x轴正方向成120°角，若粒子穿过y轴正半轴后在磁场中到x轴的最大距离为a，则该粒子的比荷和所带电荷的正负是（　　）

A．，正电荷

B．，正电荷

C．，负电荷

D．，负电荷
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