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作文。 文中共有10处语言错误，每句中最多有两处。每处错误仅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。
删词：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。
Ten years ago, I had worked as a night guard in a factory. On a rainy night, all the lights of factory went out all of a sudden. I rushed out and could see nothing. Lucky for me, the warning system was directly connected with the police station. Three or four minutes late, four police car arrived at the front gate. They searched for the factory carefully, tried to find something unusual. In the end, I am told that the rain had brought about the short circuit, that caused the accident.