1 . With the development of science, many inventions have changed our life. For example, since the cell phone _________ invented, it has done a lot for us. There is no doubt that the world has become _________ than before because of this invention. It’s much easier to get in _________ with our family and our friends living far away. We can use it to contact with people in any part of the world, and two friends can use cell phones _________ messages to each other. Their friendship will form in this way. And they can share happiness _________ each other all the time.

_________ cell phones help us a lot in our daily life, they bring us some problems, too. Using cell phones too often is bad for _________ health. They make too much noise that influences our life.

Students _________ have cell phones may use them to play games or send messages in class, because they are too young to control themselves. This will certainly do _________ bad to their study. So we should _________ the cellphones in a proper way.