短文改错

Dear editor，

I am a high school student. A few days before，one of my very good friend told me that he was going to stop school. He said that he wanted to start his own business. I tried my best to get him change his mind, but failed. I know it is difficult of him to change his mind. He is not doing so good in his studies, yet I want to insist that I give it a try. The process is important than the results. Now there are only 90 days leaving before the test. I am not sure that his decision is right or wrong. I needed your advice.

以下关于短期劳动力需求的说法正确的有（）。

A.竞争性企业的短期劳动力需求曲线是劳动力边际收益曲线的下降部分

B.在短期中，企业的劳动力边际收益曲线就是它的劳动力需求曲线

C.劳动力边际收益反映的是每增加一个工人所增加的产品增量

D.劳动力的边际收益等于劳动力边际产出量的价值量

E.劳动力的边际收益是理解短期劳动力需求曲线的核心概念