题目

静止在光滑水平面上的物体,受到一个水平拉力的作用,该力随时间变化的关系如图,则（    ） A．2s内位移为零 B．2s末速度为零 C．2s内拉力做的功为零 D．4s内拉力做的功为零 答案：BCD—How was your recent visit to Qingdao? —It was great. We visited some friends, and spent the ________ days at the seaside. [　　] A．few last sunnyB．last few sunny C．last sunny fewD．few sunny last