题目

分类法是学习化学的一种有效方法．下列物质可与：NaCl、MgSO4、AgNO3归为一类的是（） A . CaCO3 B . NaOH C . H2SO4 D . CuO 答案：AThe two girls are so alike that strangers find ______ difficult to tell them apart.A. it B. them C. her D. That