请改正下面短文中的错误。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；
删除：把多余的词用斜线（＼）划掉；
修改：在错的词下画一横线，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。
Yesterday afternoon, our school held on a fire drill. We were listening the teacher carefully in the English class when we heard the fire alarm. The teacher told us to calm down and instruct us to leave a classroom in order immediately. When we got into the passage, we found they were surrounded by smoke. It was becoming difficult to breathe but to find tine way out. Finally, with our mouths covering with wet towels, we bent down and got out of the teaching building so quickly as possible. Through the fire drill I now realize what dangerous it is when there is a fire and that we should know how to escape from a fire on case of emergency.
