Teachers have to constantly update their knowledge in order to maintain their professional __________.
Most disaster experts believe there is the potential ______ things could get a lot worse.
It ______ to me that I should go to attend a meeting when I was about to go home.
Almost all of his time ______ experiments, he has no time to visit his parents.
No government can justly claim authority ______ it is based on the will of the people.
Tom ______ with his grandmother for eight years,but now he is living by himself.