某道路工程划分为3个施工过程,在5个施工段组织成倍节拍流水施工,流水节拍值分别为4、2、6天,该工程的流水施工期为( )天。
A.28
B.16
C.20
D.14
参考答案:C
Kate and Mike do ____________ homework in the evening. [ ]
A. one's
B. his
C. her
D. their
设平面
则平面π1与π2的关系为( ).
A.平行但不重合B.重合C.垂直D.既不平行,也不垂直