Prof. Zhao obtained his PhD from Columbia University after his BSc from USTC.  He worked in various instututes, including as a UK Research Coucil Advaced Fellow in Institute of Astronomy, Cambridge, and is presently tenured in University of St Andrews, UK.Is there a way to obtain its mean gravitational potential directly without measuring its rotation curve?  I discuss important relativistic effects which I propose that the CSST should explore to learn dynamics of galaxies with slitless spectrography.  I will discuss its timely applications on puzzles around the CMB Cold Spot and the Local KBC void.