Her mother ________ the girl to leave the house before she had finished her homework.[ ]

A. prevented  

B. banned

C. forbade  

D. prohibited

硅酸盐水泥水化产物中，对水泥石的粘结力和强度起主要作用的是（）。

A．水化铝酸钙

B．水化硅酸钙

C．水化铁酸钙

D．氢氧化钙