题目

— Excuse me. When can we play badminton at the court?  —Not until it _______ next week. A. repairs                B. will repair          C. will be repaired                       D. is repaired 答案：D18．A、B两球在光滑水平面上沿同一直线运动，A球动量为PA=5kg•m/s，B球动量为PB=7kg•m/s，当A追上B时发生碰撞，碰撞后A、B两球的动量可能是（　　）A．PA=6kg•m/s，PB=6kg•m/sB．PA=3kg•m/s，PB=9kg•m/sC．PA=-5kg•m/s，PB=17kg•m/sD．PA=-3kg•m/s，PB=14kg•m/s