Only by imagining and creating ____the problem.
Which do you enjoy _____ your weekend, swimming or fishing?
As ___rule, apples are sold by_____weight and eggs by _____dozen.
—No wonder you caught a cold. You ________out last night without a coat. —I know how silly I was.
Smallpox, a kind of disease, has now died ________.
The discovery of new evidence led to__________