【单选题】铸铁焊接裂纹一般为冷裂纹,产生温度在()摄氏度以下,产生部位为焊缝或热影响区。
【简答题】带传动设计中,为何要限制小带轮的最小基准直径?
【单选题】铸铁焊接裂纹一般为冷裂纹,产生温度在()以下,产生部位为焊缝或热影响区。
【单选题】We ___________ on it for many hours, but we have not yet reached any conclusion. A. are being worked B. are working C. have been working D. have been worked
【判断题】按决策的结构,决策问题可分为确定型和不确定型二种。