单项选择题
He ()his tie as soon as he walked out of the office building.
A.unfoldB.undidC.unloadedD.undo
单项选择题 The evergreen shrubs struggled to ()the dust and fumes from the busy main road.
单项选择题 Computer is ()storing millions of bits information.
单项选择题 He tried to show me how it ()but he couldn ’t make it roll back up the string.