题目

一物体在空气中用弹簧测力计测得它的读数为G，把它浸没在水中后弹簧测力计测得它的读数为1/3G，则这个物体的密度为（ ） A . 0.33×103千克/米3 B . 0.67×103千克/米3 C . 1.5×103千克/米3 D . 2×103千克/米3 答案：C—Tomorrow is a holiday. Why are you doing your homework now?     —I am doing these exercises so that I won’t have     tomorrow. l A．to     B．it   C．them D．for