短文改错

假定英语课上老师要求同桌之间交换修改作文，请你修改你同桌的以下作文。

文中共有10处语言错误，每句中最多有两处。错误涉及一个单词的增加、删除或修改。

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。

修改：在错的词下划一横线，并在该词下面写出修改后的词。

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。

A sports meeting was held in our school several days before. The last event was the 400-meter relay race, that had promised to be an exciting one. And so it was! Teams from every class joined in the race, but the winning team would be the champion of our school! So each player tries hard to win. The big crowd became quite silently and all of them had their eyes were focused as the team took their places. Heard the sound of the gun, the runners shot quickly and passed the relay sticks from one to another. Suddenly a runner from class 4 dropped his stick, but another runner picked them up and ran even faster. At the finishing lines, the runners from our class breasted the tape. Our class took a first place. Everyone cheered wildly and we felt extremely proud.

化简：

（1） 5m﹣7n﹣8p+5n﹣9m﹣p

（2）（5x²y﹣7xy²）﹣（xy²﹣3x²y）