单项选择题
A.10s±2s,20mm±2mm,1NB.10s±2s,25mm±2mm,10NC.10s±2s,25mm±2mm,1ND.10s±2s,20mm±2mm,10N
A.1B.2C.3D.4
A.查找原因,调整材料用量B.重新取样另测C.混凝土和易性不好D.混凝土配合比不合理