One of the most important inventions in the 20th century _is____(be) the computer.It has been changing all our lives since then.
The first computer _was built___(build) in 1946.It _was__(be) as large as a room and very difficult and slow to use .But since the invention of silicon"chip",computers _have become___(become) smaller,easier and faster to operate.Some computers _are__(be) as small as TV sets.Some can even be made smaller than a book.And computers _are getting____(get)smaller and smaller all the time.Who _knows__what the computers of tomorrow _will _be__(be)like?
There __are__(be) several reasons why the computer is very important to us.First,a lot of informatian can be put into computer.Second,the computer works very quickly-thousands of times faster than a man and it _isn't___(not be)tired.Third,modern computers can be built into other kinds of machines,like radios,cars,and planes.So today people can spend less time doing more work
