题目

 He was working quietly, with all his attention _______ on the task.    A. was fastened               B. fastening                  C. to fasten                   D. fastened 答案：D将函数f（x）=sin（ωx+?）（ω＞0）的图象向左平移个单位，若所得的图象与原图象重合，则ω的最小值是________．