砂浆的立方体抗压强度试件尺寸为()mm。
A.100
B.150
C.40
D.70.7
参考答案:D
Jim _____ on the computer when his father returned home.
[ ]
A. works
B. worked
C. was working
D. is working
游乐设施进出口的台阶宽度不小于()mm,高度为()mm,阶梯的坡度应保持一致。
A、200mm,150~200mm
B、210mm,200~250mm
C、220mm,150~250mm
D、240mm,140~200mm