题目

Like many families in Sanyati, a small countryside town in western Zimbabwe（津巴布韦）, Johnson’s family does not have a television. One day after school, Johnson arrived home and 41.______ something unusual in the house. At first, he 42.______ his father had bought a television, but when his mother said it was a computer, he was 43.______. It’s not that Johnson didn’t like the 44.______; he just didn’t know how to use it. Johnson and his father didn’t even know how to turn it on. Nobody in our neighborhood knew how to 45.______ a computer, Johnson said. But things 46.近年，许多不法面粉加工厂在面粉中添加溴酸钾以使面粉变白，但是溴酸钾（KBrO3）会导致人的中枢神经紊乱，引发癌变，卫生部发出通知：从2005年7月1是起禁止在面粉中加溴酸钾．KBrO3中Br元素的化合价为（　　）A．+1B．+3C．+5D．-1