a
)
He
____________________
____________________
(
learn
)
three
languages
by
the
time
he
____________________
(
be
)
20
.
b
)
When
I
____________________
____________________
(
eat
)
the
hot
dog
,
I
____________________
(
start
)
feeling
sick
.
c
)
Before
Julie
____________________
(
move
)
to
Colombia
,
she
____________________
____________________
(
live
)
in
Argentina
.
d
)
By
the
time
he
____________________
(
die
)
,
he
____________________
____________________
(
write
)
10
books
.
e
)
We
____________________
____________________
(
not
be
)
excited
because
we
____________________
____________________
(
visit
)
the
Space
Center
three
times
before
.
f
)
She
____________________
(
be
)
surprised
because
she
____________________
never
____________________
(
see
)
a
rokcet
before
.