气硬性胶凝材料只适用于( )环境。
A．潮湿
B．地下
C．水中
D．地上
参考答案：D
It’s _______ you do today that will make a difference in your life tomorrow.
A．what
B．that
C．how
D．which
A．255.255.255.0
B．255.255.0.0
C．255.0.0.0
D．0.0.0.0
