【判断题】力偶是特殊力系,只产生转动效应,没有移动效应
【简答题】A.constant B.persisting C.stable D.lasting
【单选题】40Cr制造的齿轮,应选用__________作为预备热处理
【判断题】施工升降机的维护保养分为:定期维护保养,特殊维护保养和闲置保养。()
【单选题】40Cr 制造的齿轮 , 应选用 ______ 作为预备热处理
【单选题】When We reached the station the train had not arrived yet;so we_______.
D.
had not needed to hurry
【单选题】Resveratrol is the fourth factor recently found that causes a breast cancer to develop.
【判断题】力偶是特殊力系,只产生转动效应,没有移动效应。
【简答题】A.had B.enjoying C. D.lasting