反应4A（g）+3B（g）═2C（g）+D（g），2min后B的浓度减少0.6mol•L﹣1．对2min内反应速率的表示正确的是（ ）
A：用A表示的反应速率是0.3mol•L﹣1•min﹣1
B：分别用B C D表示的反应速率其比值为3：2：1
C：在2min末的反应速率，用B表示是0.3mol•L﹣1•min﹣1
D：在2min内用B表示的反应速率的值是逐渐减小的，用C表示的反应速率的值是逐渐增大的
下列做法中体现自尊的是（ ）
假定英语课上老师要求同桌之间交换修改作文，请你修改你同桌写的以下作文。文中共有10处错误，每句中最多有两处。错误涉及一个单词的增加、删除或修改。
注意：修改10处，在横线上写出错误指出，并加以修改。
Hi,Susan
I’m sorry that I wasn’t able to return to your bike on time yesterday. I mean to give it back to you before four in the afternoon，and I was hold up on my way back. Just before I turned corner of park street. I happened to see an accident. A little girl was hurt and mother needed help. So I helped them going to the nearest hospital. I stayed here for one and a half hour and made sure that the girl was all right.When I got back, it were already 6 pm. I hope you understand.
Thank you!
Li Ling
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