Today,I heard a story that is mainly about a lesson of a careless boy:A boy thought he was old enough to do things well,so he paid little attention to his father's words.As a result out of his careless he almost hurt his leg,then he knew that it was important to be careful.

    I have a similai experience,I used to be a careless girl and I got a lesson in an important exam.Before the exam,I had done many things to prepare it,I had done many excises,arranged all the note and went over all the lessons.Then I felt so expectful  that I thought I must got a good mark.Because I was too confident,so I ignored my teacher's words which told us not to be so nervous and to check the paper after we finished it.

    However,as soon as the test began,I began to write down my answer hurrily,forgetting the most important thing-to write my name and number!What's worse was that I didn't check the paper.Finally,though my answer was correct,I still got a "zero".

    From the experience,I know that the carelessness is very dangerous,it will become the subconsciousness which can make us hurt ourselves invisibly.So I will be more careful and patient from now on!