【判断题】西门子人机界面的RS-485接口可以使用MPI/PROFIBUS-DP通信协议。
【单选题】______ market research has shown that most Americans prefer environmentally-friendly products.
【单选题】Tree Co is considering employing a sales manager. Market research has shown that a good sales manager can increase profit by 30%, an average one by 20% and a poor one by 10%. Experience has shown that...
A.
Do not employ a sales manager as profits would be expected to fall by $1,300
B.
Employ a sales manager as profits will increase by $38,700
C.
Employ a sales manager as profits are expected to increase by $100
D.
Do not employ a sales manager as profits are expected to fall by $39,900
【单选题】水泥砂浆的养护温度和湿度是:温度( ),相对湿度( )以上。
【判断题】砌筑砂浆抗压强度等级是以边长为70.7mm的正立方体试件在标准养护条件(温度:20℃±3℃。相对湿度:水泥混合料砂浆为60%~80%,水泥砂浆和微沫砂浆为90%以上)下,28d抗压强度的平均值确定。