在下列命题中，正确的是[      ]

A．一组对边平行的四边形是平行四边形

B．有一个角是直角的四边形是矩形

C．有一组邻边相等的平行四边形是菱形

D．对角线互相垂直平分的四边形是正方形

下面短文中共有10处语言错误，请在有错误的地方增加、删除或修改某个单词。

增加：在缺词处加一个漏字符号（^），并在其下面写出该加的词。

删除：把多余的词用斜线（\）划掉。

注意：

1. 每处错误及其修改均仅限一词；

2. 只允许修改10处，多者（从第11处起）不计分。

Hello, boys and girls! Today, I am going to talk with what you should do when a fire alarm go off. If you hear the alarm, stand in line at the door and wait your teacher to lead you outside. Stay close to your teacher and classmate. Don't panic or get out of line, and trying to remain quiet and calmly. Soon the firefighters will come and put out a fire. If it's a false alarm and there is no fire, your teacher will lead us back to the classroom. If you notice that when someone is missing and hurt, tell your teacher immediately.