Answers of exercises

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

Times (change) have changed. Computers (become) have become powerful machines with very practical applications. Programmers (create) have created a large selection of useful programs which do everything from teaching foreign languages to bookkeeping. We are still playing video games, but today's games (become) have become faster, more exciting interactive adventures. Many computer users (get, also) have also got on the Internet and (begin) have begun communicating with other computer users around the world. We (start) have started to create international communities online. In short, the simple, individual machines of the past (evolve) have evolved into an international World Wide Web of knowledge.