以下哪种措施是经济的？（）
A.预防失效模式的发生
B.加大检测数量和频率
C.采用高度自动化的设备
D.及时采取纠正措施
参考答案：A
鲜或干的无花果
— I don't know what to buy for my mother.
— If I ____ you. I ____ a bund of flowers. [ ]
A. am; will buy
B. were; would buy
C. am; would buy
