A. 68为平底热盘,50为弧形热盘 B. 68为钢胆,50为铝胆 C. 68为气旋阀,50为磁悬阀 D. 68不可中途开盖,50可以中途开盖
A. your delaying making B. you todelay making C. your delaying to make D. you delay to make
A. 电话形式; B. 书面形式; C. 口头通知; D. 电子文档