The reason ____ he hasn’t come is ____ he has to look after his father.[ ]

A. that; because

B. why; because  

C. why; that

D. which; because

建筑工程管理方法的特点是( )。

A．缩短了工程项目的建设工期，使部分工程分批投产，提前获得收益
B．调节计划进度与实际进度的改变
C．动态控制设计进度
D．加强与业主、监理单位、科研单位与承包商的协作与配合