What are the keywords in the following sentence? Someone grabs a grenade from an open crate and hurls it into enemy ranks, exploding several hydra soldiers.
explode, grab, grenade, hurl, rank

What are the keywords in the following sentence? mist rising on a cold morning
mist, morning, rise

What are the keywords in the following sentence? a train arrives on its way
arrive, train, way

What are the keywords in the following sentence? roses in the shape of heart
heart, rose, shape