题目内容：

假定英语课上老师要求同桌之间交换修改作文，请你修改你同学写的以下作文。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。

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：在错词的下面划一横线，并在该词下面写出改后的词。

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。

There was a big fire in one office buildings in our neighborhood at about nine o’clock last night. Many firemen and fire engines come. In a beginning, we saw flames with thick black smoke coming out from the six floor. We also heard the explosion the gas tank mix with the noisy sounds from the windows. Soon the fire spread one by one to the floors above, but finally reached the top floor. Many people stood outside on the streets watch the fire in horror. Unluckily there was no one in that office building when the fire broke out in.