发展水平连铸有三大技术关键：首先是分离环的材质，寿命和成本；第二是结晶器的涂层和（）；第三是满足拉－停－反推拉坯方式的拉坯机械。
参考答案：润滑
Yesterday on the way home my father found a new-born baby_____ by its mother, struggling to survive.
A．devoted
B．defended
C．deserved
D．deserted
颅内压增高的常见病因有（）
A.脑水肿
B.脑积水
C.脑脓肿
D.颅内肿瘤
E.脑外伤
