1) American doctoral programs are called "postgraduate and doctoral programs" in China, which are basically 4-6 years, 4 years faster, 6 years slower or even longer, depending on your major. In the first two years, I have to take basic courses, that is, the "master's stage", and in the next few years, I have to follow my boss to do projects and issue papers, that is, the "doctor's stage".

2) At present, as long as you accept the doctoral program in the United States, you basically don't need to pay. The school will waive your tuition. You have to work as a teaching assistant at school with a monthly salary, so you have living expenses.

3) If you apply for a doctoral program in a public university, the university thinks that you do not meet the admission criteria, but you have certain potential and will be downgraded to a master's degree. Some students only apply for a master's degree at first, then follow the professor's efforts, and then naturally follow others to continue their doctoral studies.

4) But recently, some schools are short of funds, especially in business. Even if they are admitted to the doctor's degree, they may not have the money to make money. This needs to be communicated with specific schools.