题目

如图2，天秤中的物体a、b、c使天秤处于平衡状态，则物体a与物体c的重量关系是    A. 2a=3c         B. 4a=9c        C. a=2c           D. a=c  答案： 解析:略 —What a nice MP4! Whose is it? —Mary was listening to music just now. I think it must belong to _____. [     ]A. her B. she C. hers D. Mary's