"随便打蓝松鸟，如果你能打中它们；但记住，杀死一只知更鸟是一种罪过。"

Simplified Meaning:

This quote means that it's okay to deal with things that cause trouble or harm, but it's wrong to hurt something that is innocent and only brings beauty or help to the world. Imagine you have a garden. Bluejays might come and peck at your fruit, making a mess and ruining your hard work, so it's understandable to get rid of them if they are causing problems. On the other hand, mockingbirds just sing beautiful songs and don’t harm your garden at all. Hurting a mockingbird would be unfair because they only offer something good without causing any issues. In your life, think about how you treat people. It's okay to stand up to someone who is causing trouble, like a bully who makes school hard for everyone. But it's not right to hurt or be unkind to someone who is innocent and just trying to live their life, like a person who is kind and helps others. Being fair and kind to those who do no harm is important for a just and caring world. Treat those who mean no harm with respect and protect them, just like you would want others to do for you.