We
use
____________________
as
the
past
tense
of
can
.
We
use
____________________
to
show
that
something
is
impossible
.
We
use
____________________
to
talk
about
someone's
skill
or
general
abilities
.
We
use
the
modal
____________________
to
make
general
statements
about
what
is
possible
.
We
use
"
be
able
to
"
to
talk
about
____________________
.
The
structure
of
"
be
able
to
"
is
-
subject
+
be
+
able
+
____________________
.
They
____________________
have
arrived
hours
ago
.
He
was
obviously
joking
.
He
____________________
be
serious
.
We
use
"
could
you
"
as
a
____________________
way
of
telling
or
asking
someone
to
do
something
.
