题目内容：

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处语言错误，每句中最多两处。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，并在其下面写出修改后的词。

注意：1.每处错误及其修改均仅限—词；

2.只允许修改10处，多者（从11处起）不计分。

A terrible fire happened in one office building in our city at about nine o'clock last night.

In the beginning, we saw flames with thick black smoke coming out from the five floor, and we also hear the explosion of the gas tank. It was said what the fire started at the first floor, spreading one by one to the floors above, but finally reached the top floor. Some windows and brick wall were burnt down because the heat of the fire. Many people stood outside on the streets watch the fire in horror. Many bravely firemen and fire engines came quickly. Luckily, there was no one person in the office building when the fire was broke out. It took about two hours for the firemen to put out a big fire.