—Have you ever been to Qufu?—Yes. I went there last year. It’s a very _______ place.
—It smells terrible. What has happened here?—Look, there is much waste gas _____ from the chemical factory.
—Have you finished your homework?—Not _____. There are still some exercises to be done.
_____ the environment is important for human beings.
This is the most beautiful park I have _____ visited.
Xi’an is a city with many places of interest and __ tourists come here every year.