A good teacher must _____ to his students the importance of a proper learning method.
How long do you think it will be _______ scientists succeed in providing a cure for cancer?
When my father lost his job our living _______ had to be cut to the bone.
The two naughty boys were quiet when eating, and they were accustomed to ______ at meals.
This novel is _______ that one, so I like neither of them.
If I had followed her advice and worn _______ warm clothing, I wouldn’t have caught such _______ bad cold.