高炉的碱负荷
参考答案：
冶炼每吨生铁入炉料中碱金属氧化物（K2O+Na2O）的千克数；
刚倒入杯子的开水很烫，人们习惯吹几下再喝；冬天写作业时手冷，习惯哈哈气再写．是分析这两种做法分别包含的物理道理．
--- What about inviting Mary to our party?
--- You’d better not. She prefers to be ____, so far as I know.
A．tested out
B．rung up
C．left alone
D．turned around
