As is known to all language learners, newly learnt words will soon be forgotten unless ______ used in everyday communication.
With a lot of difficult problems ________, the newly-elected president is having a hard time.
Tony was very unhappy for _______ to the party.
Though ________ money, his parents managed to send him to university.
The research is so designed that once _______ nothing can be done to change it.
“What do you think made Mary so upset?” “_______ her new bike.”