Jack started to work at ______ early age because his family was very poor. [ ]

A. a

B. an

C. the

D. /

对施工项目而言，编制施工成本计划的主要作用是______。

A) 确定成本定额水平
B) 对实际成本估算
C) 设立目标成本
D) 分析影响成本的因素