Simple. In order to get a degree, graduate students must defend their graduation thesis. If the defense fails, you can only get a diploma, not a degree certificate. It's usually no problem to write a thesis for half a year and prepare well.

Beijing university of chemical technology (North China), founded in 1958, is located in Beijing. It is a national key university directly under the Ministry of People's Education of China, and it is also a "985 Engineering Advantage Discipline Innovation Platform", "21Project" and a national "double-class" construction.