状态监控的趋势分析是帮助（）.
A.成本计算
B.效益分析
C.识别故障，指示误差，评估性能保持时间
D.制定维修工作范围
参考答案：C
下列是软膏烃类基质的是
A．羊毛脂B．蜂蜡C．硅酮D．凡士林E．聚乙二醇
The students are going to raise some money the poor the afternoon of May 21st.[ ]
A. to; on
B. for; on
C. to; in
D. for; in
