题目

— Why didn’t you go to see the film yesterday? —Because there was ____________. A.anything interesting  B. something interesting  C. nothing interesting 答案：C一物体做匀变速直线运动，当t＝0时，物体的速度大小为12 m/s，方向向东；当t＝2 s时，物体的速度大小为8 m/s，方向仍向东，则当t为多少时，物体的速度大小变为2 m/s (　　) A．5 s                               B．4 s C．7 s                               D．8 s