含油饱和度是指在储油岩石的（）孔隙体积内原油所占的体积百分数。
A、有效
B、绝对
C、相对
D、总
参考答案：A
下列小儿运动发育中哪项最正常
A．6个月时抱起能竖头
B．8个月稳坐且会爬
C．10个月会坐
D．12个月能站立
E．18个月独立行走
Our car ______ on our way to school, so we had to walk there.
A．broke up
B．broke off
C．broke down
D．broke away
