  The Heavy quark effective field theory (HQEFT) is revisited in a more
intuitive way. It is shown that HQEFT is a consistent large component QCD of
heavy quarks. In the non-relativistic limit, HQEFT recovers the
non-relativistic QCD (NRQCD). The resulting new effects in the HQEFT of QCD are
carefully reexamined. It is then natural to come to the comments on the usual
heavy quark effective theory (HQET). Consistent phenomenological applications
of HQEFT exhibit its interesting features and completeness in comparison with
HQET. It then becomes manifest why we shall base on the HQEFT of QCD rather
than HQET which is an incomplete one for computing 1/m_Q corrections. More
precise extraction for |V_{cb}| and |V_{ub}| in the HQEFT of QCD is emphasized.
