由水垢结晶形成的污垢属于（）。
A、碳氢凝聚物沉积
B、无机盐类沉积
C、生物污垢粘附
D、金属锈蚀
参考答案：B
Father's Day is on the Sunday of June while Mother's Day is on the Sunday of May. [ ]
A. third; third
B. second; second
C. third; second
D. second; third
