To date, there have been no long-term studies on the effects of cell phone usage among children.
到目前为止，没有做过儿童中长期使用手机的研究。
Results from individual participating countries have suggested an association between more than 10 years of mobile phone usage and some tumours.
个别参与国的调查已经表明了连续10年以上的手机使用和肿瘤的某种联系。
Internet usage, mobile phone usage, advertising dollar spend - all have grown enormously over the last 15 years to provide a stronger foundation underneath the latest boom.
互联网应用、手机应用、广告支出——所有这些在过去15年中都有了巨大的增长，为最新一轮繁荣提供了更强有力的支持。
In the long run most national differences will disappear, predicts Scott Campbell of the University of Michigan, author of several papers on mobile-phone usage.
密歇根大学的ScottCampbell写过几篇有关移动电话使用的论文，他预测说：长远来看，不同国家间的差异最终多数会消失。
In the long run most national differences will disappear, predicts Scott Campbell of the University of Michigan, author of several papers on mobile-phone usage.
密歇根大学的ScottCampbell写过几篇有关移动电话使用的论文，他预测说：长远来看，不同国家间的差异最终多数会消失。
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