About
____________________
years
ago
,
human
beigns
began
to
make
____________________
objects
.
The
first
metal
they
used
was
____________________
,
but
it
was
not
very
____________________
.
Later
,
they
used
____________________
and
____________________
to
make
tools
,
weapons
and
____________________
.
There
were
three
important
inventions
:
-
The
____________________
,
which
greatly
improved
____________________
.
-
The
____________________
,
which
meant
than
____________________
could
be
bigger
because
they
used
the
force
of
the
wind
.
-
The
____________________
,
which
made
working
the
____________________
easier
and
faster
.
The
use
of
metal
objects
was
a
sign
of
great
____________________
,
and
caused
many
____________________
.
The
search
of
metals
to
make
tools
created
new
____________________
____________________
.
Trade
produced
____________________
,
and
villages
turned
into
____________________
.
New
professions
,
such
as
____________________
,
craftspeople
,
priest
and
____________________
appeared
.
Wealth
was
divided
____________________
,
and
____________________
____________________
were
created
.
