假如你是李华，你的美国朋友Carl 在学汉语时遇到下图中的成语，他来信向你求助，希望你能告诉他这个成语的寓意以及在什么情况下使用这个成语合适。请用英语给他回信。
注意：
1．词数100左右；
2．可以适当增加细节，以使行文连贯。
参考词汇：羊圈：sheepfold；牧羊人：shepherd
解释成语亡羊补牢的寓意和用法英语作文范文
Dear Carl，
I am happy to know that you are getting along well with your Chinese.It's quite natural that you should have difficulties with Chinese idioms, because their meanings are so much different from their apparent meanings.
The original meaning of the idiom attached is that when the shepherd found his sheep missing because of the broken sheepfold , he was advised to mend it in time.Today, the moral of the idiom is that when you make a mistake and do something wrong, you should correct it as soon as possible.It is somewhat equal to an English phrase Late better than never．For example, you can use the idiom to encourage your friend to work harder to make up the time he has wasted.Hope you will make more progress!
Best regards!
Yours，
Li Hua