try to translate these sentences please
.(用中文直接按字面的意思翻,不要用自己的语言理解的那么翻,
Unfortunately.Babbage never assembled his computer.and it was not until the 1900S,with the invention of the electron tube,that components for a viable electronic computer became available.
An electron tube is a device that can block,amplify,or act as an on/off switch for an electric current.During the 1920S and 1930s,
scientists investigated how to link these devices in arrays that would accept electric signals representing numbers,process the signals according to programme,and output the results.whereas electron-tube computers were huge,and programming them involved changing their circuitry by plugging and unplugging cables.