What do you think is the most useful invention of all time？
By Cindy Wu	There are many the train， the car， and the airplane the useful machines， but these are not my ____． For an everyday， useful invention， I vote for the air conditioner． I live in Taibei， and during the summer the temperature can be 39 degrees Celsius or more． It's so hot! I'm not joking when I said that， if there are no air conditioners， people here cannot work or study． A lot of people might also get sick____ cool air．
By Jorge	The most useful invention of all time is surely the Internet． We can now reach people and do business faster． I ___ a clothing store in Mexico City， and there's a lot of competition． I not only have a website as others， but also own a online store on Taobao．com． Now， people from all over the world can buy my clothing using the Internet． I can keep in touch with friends and family in Mexico and around the world using e mail． It's faster than____ mail， and it's cheaper than using the phone!
By Kazuo	I also think that the Internet is useful． But， in my opinion， there is an "invention" that is even more ____， and that's electricity． Of course， this is not a man﹣made invention， but people like Benjamin Franklin and Alessandro Volta learned how to use it． If there is no electricity， many of the world's greatest inventions would not ____．