Boundaries are important in general, but they become especially important when you're dealing with toxic people. Toxic people often take advantage of people with poorly defined boundaries and low self-assertiveness. Here are some steps to help you maintain better boundaries:  Tune into and act on your feelings. Avoid getting swept up in the emotional turmoil of toxic people. Pay attention to what you feel and need. Give yourself permission to be firm. Many people feel guilty if they have to establish a firm boundary. However, taking care of yourself is also important. Avoid neglecting yourself in favor of others. Learn that saying no doesn't make you a bad person. It's easy for some people to make excuses for a toxic person. You may know deep down that the person is bad for you or is taking advantage of you. Avoid rationalizing these gut instincts or explaining their behavior away. Let your instincts have the final word, because they probably know more about what's going on and what you need than you realize. Learn to know when enough is enough and you need help. Contact a close friend or family member you trust to be there for you. If you want to maintain relationships with toxic people, be sure to make use of your support network. Keep self-care a priority. Giving too much of yourself is not the best way to be there for other people. Try to make a sober assessment of the kind of relationship you're in and the effect it's having on you. Many people who continue being friends with toxic people have a "people pleaser" personality, where they want to be liked and want to feel like they're supporting others. There's nothing wrong with being supportive, but be aware of what's going on so that you can have a realistic picture of the situation. If the situation is hurting you, that's something you should know about. If it's enabling the other person and preventing them from change, that's something else you should know. Ask yourself these questions to get a sense of whether or not you're being indiscriminately...

TL;DR in Chinese:
划清并保持界限。 听从自己的直觉。 寻求帮助。 为自己的所作所为负责。 走开。