The physics of the central engine includes the following aspects: 1) The dynamics of the accretion flow; 2) Relativistic jets, the generation of wind and its physical properties, the formation of BLR and NLR; 3) Radiation of accretion; 4) The supply of materials to the black hole. What is the distribution of accretion rates in the sample up to 300,000 quasars? 5) The interaction between the radiation, outflow and gas in galaxies, and its influence to the star formation and the evolution of black hole mass.

How to get the geometry and kinematics of the BLR from the observation data? What is the spatial distribution of the clouds? Is the BLR consist of clouds, or continuous fluid, or a mixture of the two? The dynamics is mainly controlled by 1) The gravity of the black hole, 2) radiation pressure, 3) the friction of thermal medium. What are the profiles of emission lines and their response to continuum variations? Is BLR inflow or outflow? How to answer these questions from the data? The large sample of reverberation mapping observation, the calculation of photoionization and accretion disk model, and the calculation of the reverberation mapping and fundamental plane, will give explicit answers to those questions.