As is known to all language learners, newly learnt words will soon be forgotten unless ______ used in everyday communication.
The trapped children ______ what had happened.
--- How long has this bookshop been in business? --- _________ 1985.
Helen said that they ________ for 3 years.
I was about to go to bed _____ someone knocked at the door.
I’ll give the diamond to _______ needs it.