A man may usually be known by the books he reads _____ by the friends he keeps.
---Someone’s been here. Who ___ it be? It looks like Helen. ---It ___ be Helen.She is ill in hospital.
Do you know what ___ while you were away from home?
He was __ twenty when he was gone.
The girl ___ in front of me kept laughing and crying.
--Do you hear a fire ___ last night?---Yes, it __ by the firemen in no time.