In
Britain
there
are
several
mobile
phone
____________________
including
Vodaphone
,
O2
,
T
-
mobile
and
Orange
.
There
are
also
____________________
like
Virgin
Mobile
who
use
the
network
of
another
company
.
When
you
buy
a
____________________
phone
,
you
have
a
choice
of
____________________
.
The
most
popular
is
'pay
-
as
-
you
-
go'
,
with
customers
paying
for
their
calls
in
advance
.
They
can
____________________
up
their
accounts
in
shops
,
over
the
internet
,
and
at
cash
machines
.
Heavy
____________________
may
prefer
a
____________________
.
They
pay
a
____________________
amount
every
month
,
but
the
calls
are
much
cheaper
than
they
are
for
pay
-
as
-
you
-
go
customers
.
Mobile
phones
usually
come
with
a
SIM
card
already
____________________
.
If
you
take
the
phone
abroad
,
you
may
be
able
to
use
it
on
a
local
network
.
This
is
called
____________________
.
It
can
be
expensive
,
and
it
may
be
cheaper
to
buy
a
foreign
SIM
card
.
