Beihang University is a comprehensive national key university directly under the Ministry of Industry and Information Technology of the People's Republic of China, a national key construction university of "985 Project" and "21Project", and one of the first batch of 16 national key universities.
Few people graduated from Beihang University for three years with a doctor's degree in engineering. It is normal for students to study for 4-5 years, and some have graduated for more than 6 years.
Doctor's situation is more complicated, facing many problems such as study, work, thesis, life, marriage, career and even age. To sum up, it is easy to study for a doctorate, but difficult to graduate.