There is no need to harm people, and there is no need to prevent people. This is the most basic principle of making friends. Then, in the process of making friends, we should first treat each other equally and honestly. What you pay is your heart, not your interests and others, and then you will see people's hearts for a long time. No matter what friends you have, you have to wait for the director to know them thoroughly. Therefore, making friends is also an art, which needs to be paid with heart.