Teachers
have
expressed
concern
____________________
the
effects
____________________
TV
____________________
some
of
their
students
.
They
believe
there
is
a
link
____________________
the
fact
that
some
students
fall
asleep
in
class
and
the
increase
____________________
the
amount
of
TV
they
watch
.
Being
so
tired
obviously
has
an
influence
____________________
their
ability
to
learn
,
and
an
impact
____________________
their
behavior
.
Staying
up
late
watching
TV
or
playing
video
games
is
one
cause
____________________
teenagers'
tiredness
.
this
is
not
just
because
they
spend
less
time
in
bed
.
The
results
____________________
several
studies
suggest
another
reason
____________________
students'
lack
of
sleep
;
after
several
hours
watching
a
screen
,
it
can
take
a
long
time
for
the
mind
to
relax
and
"
switch
off
.
"
This
means
that
even
if
they
go
to
bed
at
a
reasonable
time
,
they
are
unable
to
fall
asleep
immediately
.
