题目

（湖北省部分重点中学2009届高三第一次联考） A Last week，Bill Gates retired from full-tine．rime work at the world’s biggest computer software company, Microsoft．He will remain chairman of the company he established with Paul Allen in nineteen seventy-five． Mister Gates leaves Microsoft at a time of change in the computing industry．Microsoft grew at a time when personal computers，or PCs，were replacing big mainframe computers as the main computing tools．He showed that huge profits could be made in software as PCs increasingly were found “on every desk 向某稀硝酸溶液中加入5.6 g铁粉，充分反应后,铁粉全部溶解并放出NO气体，溶液质量增加3.4 g，则所得溶液中Fe2+、Fe3+的物质的量浓度之比为A．1/1 B．2/1 C．3/2 D．4/1