请根据以下图表和提示，用英语写一篇关于我国居民手机拥有量变化的报告，并阐述手机给人们生活所带来的利与弊。

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One possible version:
 
As can be seen from the chart, great changes have been taking place in the ownership of mobile phones in China. The number of mobile phone users has been increasing rapidly these years. At the end of 2007, there were about 400 million mobile users. In the year 2010, the number  has reached 740 million.
People have found mobile phones very convenient. They can get in touch with each other whenever and wherever they like. There are many different functions for different needs, such as sending short messages and surfing the Internet. However, it may also bring us some trouble. For example, some people may take others in and commit a crime through sending short messages, and the radiation from the phone may do harm to our heath. In spite of this, the number of people having mobile phones is still increasing greatly.

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