He devoted himself ________ to his research work, having no time to play.
He is a man of few words, and seldom speaks until _______ to.
Though I have often heard this song _______. I have never heard you _______ it.
Tony was very unhappy for _______ to the party.
The research is so designed that once _______ nothing can be done to change it.
After graduation she reached a point in her career __________ she had to decide what to do.