A、B两明渠均匀流,流量相等,且断面形状尺寸、水深都相同,A的粗糙系数是B的2倍,渠底坡度A是B的()。
A.0.5倍
B.1倍
C.2倍
D.4倍
参考答案:D
解析:
If you are in a country ______they don’t speak your language,you can show the address to the taxi driver.
A.which
B.where
C.what
D.when
设两野共面变角照射,夹角为θ,为使靶区剂量分布均匀,楔形板的楔形角a应为()
A.a=θ/2
B.tga=k×tgθ(Fw为楔形因子)
C.a=θ×Fw
D.a=180-θ/2
E.a=90-θ/2