—It is selfless   the most beautiful teacher—Yang Xiangming to lose his life     the child in the river.

—I think so, he is so great.

A．for; to save

B．of; to save

C．for; to saving

D．of; to saving

将品种法，分批法和分步法概括为产品成本计算的基本方法，因为它们（）。

A.应用最广泛

B.计算最简便

C.是生产特点和管理要求所决定

D.对成本管理最为重要