题目

Mrs. Black would rather his husband did some housework when he’s free, but he _______. A. wouldn’t          B. didn’t        C. doesn’t              D. wasn’t 答案：C 解析: 略为鉴别妈妈所戴的金戒指的真伪，小明用天平和量筒测量它的质量和体积时所得数据如图甲、乙所示，请你帮他读出戒指的质量是_______g，密度是______kg/m3，由此可判断这枚戒指______(填“是”或“不是”)纯金的．(ρ金＝19.3×103 kg/m3)