With no explanation, label each line with "product-other", "O", "person-scholar", "art-broadcastprogram", "art-film", "art-music", "art-other", "art-painting", "art-writtenart" or "building-airport" preceded by ":".
It
has
been
suggested
that
relativistic
electron
beams
could
be
used
to
heat
and
accelerate
the
reaction
mass
in
electrical
rocket
engines
that
Dr
.
Robert
W.
Bussard
called
quiet
electric-discharge
engines
(
QEDs
)
.
It:O
has:O
been:O
suggested:O
that:O
relativistic:O
electron:O
beams:O
could:O
be:O
used:O
to:O
heat:O
and:O
accelerate:O
the:O
reaction:O
mass:O
in:O
electrical:O
rocket:O
engines:O
that:O
Dr:O
.:O
Robert:person-scholar
W.:person-scholar
Bussard:person-scholar
called:O
quiet:product-other
electric-discharge:product-other
engines:product-other
(:O
QEDs:product-other
):O
.:O