题目

（2010·浙江余杭高级中学高三上第二次月考）      17. They _____ on the program for almost one week before I joined them, and now we _____ it as no good results have come out. A. had been working; are still working B. had worked; were still working C. have been working; have worked D. have worked; are still working 答案：A设[x]表示不超过x的最大整数（如[2]=2，[1.3]=1），已知函数（x≥0），当f（x）＜1时，实数x的取值范围是    ．