He thought that painting copied by a modern artist was ______ great value and bought it ____ over a thousand dollars.

A．at; for

B．of; for

C．of; at

D．for; by

下列选项中，（）是正确组织施工企业建筑产品成本核算的重要条件之一。

A．确定直接计入当期损益的对象

B．确定工程成本核算的基本要求

C．合理确定成本核算对象

D．正确划分各种费用支出的界限