After the patients went into the office,＿＿working.

A．only a doctor did they see

B．only a doctor saw they

C．only a doctor they saw

D．only a doctor had they seen

某市商业中心区建设施工，拟按子项目组成编制施工成本计划，则首先要把项目总施工成本分解到各______中。

A．单位工程

B．单项工程

C．单体工程

D．分项工程