____________________
the
____________________
point
of
the
river
.
upper
course
the
initial
stage
of
the
____________________
.
middle
course
the
water
flows
more
____________________
.
lower
____________________
its
the
final
stage
____________________
river
____________________
slowly
.
the
____________________
its
the
end
the
water
____________________
by
the
river
flow
into
____________________
river
.
