阅读下面短文，用括号内所给动词的适当形式填空 (必要时可加情态动词或助动词)。
Computer are very popular these days. People are talking about and using the Internet everywhere, but how many of us__1__ (know) the history of the Internet? Many people are surprised when they find that the Internet __2___(set )up（建立）in the 1960s. At that time computers were large and expensive. Computer network(网络)__3___(not work) well. If one computer in the networks __4___(break) down, then the whole network stopped. So a new network system had to be set up. It should be good enough to be used by many different computers. If part of the network was not working, information__5___(send) through another part. In this way computer network system would keep on__6___(work) well all the time. In the 1970s, computers were still expensive and the Internet was difficult__7___(use). Today it’s easy to get on line and it__8___(say) that millions of people use the Internet every day.
___9___( send) E -mail is more and more popular among students. The Internet_10__(become) one of the most important parts of people’s life already.