Past simple/continuous or present perfect tense

Since computer were first introduced to the public in the early 1980's techology has changed(change) a great deal .The first computer were (be) simple machines designed for basic tasks. They had not (have, not) much memory and they weren't (be, not)very powerful.early computers were often quite expensive and customers often paid (pay) thousands of dollars for machines which actually were doing (do) very little. Most computers were(be) separate, individual machines used as expensive typewriters or playing games

Times has changed (change). Computers has became(become) powerful machines with very practical applications. Programmers have created (create) a large selection of useful programs which do everytnihg from teaching foreign languages to bookkeeping. We are still playing video games, but today's games have become(become) fastre, more exciting interactive adventiure. Many computer users ----------- (get,also) on the Internet and --------(begin).