球墨铸铁的球化剂常用（）
A.硅铁
B.镁或稀土镁合金
C.硅铁和锰铁
D.都不是
参考答案：B
Changes may be requested by any stakeholder involved with the project, but changes can be authorized only by (73)．
A．executive IT manager
B．project manger
C．change control board
D．project sponsor
尤善治热毒血痢的药物是（）
A.苦参
B.葛根
C.白头翁
D.栀子
E.黄柏
