阅读下面材料，在空白处填入适当的内容（不多于3个单词）或括号内单词的正确形式。

    Until recently daydreaming was viewed as a waste of time or it ____ (consider) an unhealthy escape from real life and its duties．But now some people are taking a fresh look at daydreaming．Some think it may be a very ____ (health) thing to do．Some researchers are finding that daydreaming may be important to mental health．Daydreaming, they tell us, ____ a good means  of relaxation．But its benefits go____ this．A number of psychologists have conducted experiments and have reached some____ (surprise) conclusion．

    Dr．Joan T．Freyberg has concluded that daydreaming contributes growth．It also improves____ (concentrate),attention span, and the ability to get along with others．Industrialist Henry J．Kaiser believed that much of his success was due____ the positive use of daydreaming．Florence Nightingale dreamed of becoming a nurse．The young Thomas Edison pictured____ as an inventor．

    For these notable achievers, it appears that their daydreams came  ____．Dr Harry Emerson Fosdick offered this advice: “Hold a picture of yourself…in your mind's eye, and you will be drawn toward it．Picture yourself ____ (vivid) as defeated and that alone will make victory impossible．

已知△ABC与△ 的相似比为2：3，△ 与△ 的相似比为3：5，那么△ABC与△ 的相似比为____。