柔性风管制作，风管直径＞500mm时，板材厚度应≥____mm。（）
A.0.05
B.0.09
C.0.12
D.0.2
参考答案：D
The children were warned of not being too_________about things they are not supposed to know.
A．strange
B．amusing
C．curious
D．satisfied
降水方法可分明排水和（）
A、人工降低地下水位法
B、井点降水法
C、集水井降水法
D、轻型井点法
