One of the main __________ of the summit was “sustainable development”,or the question how we can continue developing the world without damaging the environment.
She studies ___ medicine before she turned ___ writer.
His uncle gave him books to read, but after a page or two he would put __book down and pick up__ new one.
A non-smoker can hardly imagine__ pleasure of having__ smoke after a meat.
.They have their reasons for keeping their marriage___ secret for ___ moment.
He had decided to give it up , but on____ second thoughts he decided to try___ third time.