the born step lower source middle finish mouth course source goes middle upper middle course course
STages
of
a
river
are
,
,
middle
course
,
,
and
the
mouth
.
The
first
is
the
because
its
when
the
river
,
the
is
the
latest
,
because
it
it
stage
.
The
is
the
,
because
the
river
in
of
its
.