未知题型 厚度均匀边长为30cm的正方形板，垂卣悬挂在铰链上，铰链连接o点，射流自喷嘴中水平射出冲击到板面中心后，使板面偏转一30°的角，设喷嘴直径d=0.025m，速度为v0=6m/s，计算这块方板的质量。

未知题型 下列哪项不是下肢丹毒的防护要点A．患者应卧床休息B．患者所用敷料、器械须严格消毒###SXB

单项选择题 Owing to the increase of the material price, our offer has left us with small profit, ______ we can not accept your counteroffer. A．as a result B．as a result of C．result in D．result from