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28. Be careful! The slightest spark(火花)could ______ the fireworks.
27. The police are offering a $ 60,000 _____ for information about the killer.
26. People generally think that smoking is a bad ______ .
25. We invited her to dinner but she didn’t even bother to _______ .
24. —Where does your little daughter want to go during her holiday ? —She is always looking forward to _____ to the Wu Yi Mountain.