单项选择题Which of the following is the “handy language” we use when we write a conclusion?
单项选择题已知配制C35混凝土所用普通水泥P.O52.5的实际强度是55MPa,采用碎石,其回归系数αa=0.46,αb=0.07,该施工单位的强度标准差是3.0 MPa,则W C应是:( )。 A、0.33 B、0.50 C、0.61 D、0.69