建设工程流水施工的普遍方式是( )。

A．非节奏流水施工
B．固定节拍流水施工
C．加快的成倍节拍流水施工
D．异步距成倍节拍流水施工

By the time I reached home, my parents _______the dinner for me already.[ ]

A. had cooked            

B. cooked

C. have cooked            

D. cook