剔花之所以在北方地区流行，是因为北方的瓷胎较厚，较之南方的薄胎瓷器更适合剔刻工艺。
参考答案：对
My father _____ my mobile phone because I didn't have good grades in the exam. [ ]
A. cleaned up
B. passed on
C. ran away
D. took away
离心泵流量与效率的关系是（）关系。
A、正比
B、反比
C、倍数
D、开始时呈正比
