An active volcano is a volcano that is erupting or is expected to do so in the near future.
(An active volcano; is; a volcano that is erupting or is expected to do so in the near future) (a volcano; is erupting; ) (a volcano; is expected; ) (a volcano; to do; so; T:in the near future)
An active volcano a volcano a volcano a volcano
is is erupting is expected to do
a volcano that is erupting or is expected to do so in the near future
so T:in the near future