-- _____is that used for?---_____ the floor.
30. He will not tell the fact ______she has gone to Beijing.
29. The film is ______ a film. It is also a good material for education.
28. The water will be further polluted unless some measures ______.
27. More and more Chinese women are having difficulty ______ Mr. Right or are choosing the single life.
26. He returned home very late as ______.