The red flag looks extremely beautiful _____ the blue sky and white clouds.
One summer night in 1990, a reporter appeared at the door of Thomas Edison’s laboratory, _____ for an interview.
--- Is Tom still smoking?--- No. By next Saturday he _____ for a whole month without smoking
The traditional goal of science is to discover how things are, not how they ought _____.
In their spare time, they will discuss the _____ to the study of English.
About _____ of the population of that country _____ on farms.