短文中共有10处错误，错误涉及一个单词的增加、删除或修改。
增加：在缺词处加一个漏词符号(∧)，并在此符号下面写出该加的词；
删除：把多余的词用斜线(\)划掉；
修改：在错的词下划一横线，并在该词的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。
Two years ago, our math teacher offered us an answer at a difficult math problem in class. Although an answer seemed a little strange, but only I doubted it. Thought that his answer might be wrong, I carefully considered the problem and tried to work them out in a different way. Half an hour late, I finally managed find its correct answer. When I showed the answer to him, the teacher praised me for my independence thinking.
From this experience I had already come to the conclusion whether questioning can serve as a bridge that helps us seek the truth.
