采用特殊成形工艺的混凝土和水灰比小于（），用水量应通过试验确定。
A、0.10
B、0.20
C、0.30
D、0.40
参考答案：D
-Why do you look sad?
-There are so many problems _______ [ ]
A. remained to be settled
B. remained setting
C. remaining to settle
D. remaining to be settled
在南半球，若两点间的大圆始航向为045°，则恒向线航向（）。
A．大于045°
B．等于045°
C．小于045°
D．不一定
