  Quarks of different flavors have different masses, which will cause breaking
of flavor symmetries of QCD. Flavor symmetries and their breaking in hadron
spectroscopy play important role for understanding the internal structures of
hadrons. Hadron spectroscopy with strangeness reveals the importance of
unquenched quark dynamics. Systematic study of hadron spectroscopy with
strange, charm and beauty quarks would be very revealing and essential for
understanding the internal structure of hadrons and its underlying quark
dynamics.
