问题：说近100年最important的invention之一

　　参考回答：in my opinion the most important invention of the last 100 years is mobile phone. The fist reason for why I choose it is that, by using a mobile phone, the distance between one another is significantly shortened. For example, I can send messages or make a phone call to connect with my friends in other cities no matter when and no matter where. But before mobile phone was invented, I have to wait several days at least to get some information from them.