The moment the 28th Olympic Games _______ open, the whole world cheered.   [ ]

A. declared    

B. have been declared

C. have declared    

D. were declared

方坯普通质量非合金钢和低合金钢不得有深度大于（）的裂纹，不得有深度或高度大于（）的划痕、压痕、擦伤、气孔、冷溅、皱纹、凸块、凹坑。