A
glacier
is
made
of
a
lot
of
____________________
.
When
the
snow
cannot
melt
,
____________________
snow
piles
on
top
.
____________________
the
pile
of
snow
is
thick
,
it
will
press
____________________
.
The
snow
gets
like
ice
.
Then
the
pile
slides
downhill
inch
at
a
time
.
At
the
end
,
a
big
chunk
can
split
off
and
make
an
iceberg
.